Clarithromycin is a semi-synthetic macrolide antimicrobial for oral use. Chemically, it is 6- 0 methylerythromycin. The molecular formula is C38H69NO13, and the molecular weight is 747.95. The structural formula is: Figure 1: Structure of Clarithromycin Clarithromycin is a white to off-white crystalline powder. It is soluble in acetone, slightly soluble in dehydrated alcohol, in methanol, in acetonitrile and in phosphate buffer at pH values of 2 to 5. Practically insoluble in water. Clarithromycin tablets, USP are available as immediate-release tablets. Each yellow oval film-coated immediate-release clarithromycin tablet, USP contains 250 mg or 500 mg of clarithromycin USP and the following inactive ingredients: 250 mg tablets: microcrystalline cellulose, croscarmellose sodium, pregelatinized starch, colloidal silicon dioxide, povidone K-30, stearic acid, magnesium stearate, hypromellose, hydroxypropyl cellulose, propylene glycol, talc, vanillin, titanium dioxide, and D&C Yellow No. 10 Aluminium Lake. 500 mg tablets: microcrystalline cellulose, croscarmellose sodium, colloidal silicon dioxide, povidone K-30, magnesium stearate, hypromellose, hydroxypropyl cellulose, propylene glycol, talc, vanillin, titanium dioxide, and D&C Yellow No. 10 Aluminium Lake. Structure

AND USAGE Clarithromycin is a macrolide antimicrobial indicated for mild to moderate infections caused by designated, susceptible bacteria in the following: Acute Bacterial Exacerbation of Chronic Bronchitis in Adults (1.1)

Acute Maxillary

Sinusitis (1.2) Community-Acquired Pneumonia (1.3) Pharyngitis/Tonsillitis (1.4)

Uncomplicated

Skin and Skin Structure Infections (1.5)

Acute Otitis

Media in Pediatric Patients (1.6) Treatment and Prophylaxis of Disseminated Mycobacterial Infections (1.7) Helicobacter pylori Infection and Duodenal Ulcer Disease in Adults (1.8) Limitations of Use To reduce the development of drug-resistant bacteria and maintain the effectiveness of clarithromycin and other antibacterial drugs, clarithromycin should be used only to treat or prevent infections that are proven or strongly suspected to be caused by bacteria. (1.9)

1.1 Acute Bacterial Exacerbation of Chronic Bronchitis Clarithromycin tablets, USP are indicated in adults for the treatment of mild to moderate infections caused by susceptible isolates due to Haemophilus influenzae , Haemophilus parainfluenzae , Moraxella catarrhalis , or Streptococcus pneumoniae [see Indications and Usage (1.9) ] .

1.2 Acute Maxillary Sinusitis Clarithromycin tablets, USP are indicated for the treatment of mild to moderate infections caused by susceptible isolates due to Haemophilus influenzae , Moraxella catarrhalis , or Streptococcus pneumoniae [see Indications and Usage (1.9) ] .

1.3 Community-Acquired Pneumonia Clarithromycin tablets, USP are indicated [see Indications and Usage (1.9) ] for the treatment of mild to moderate infections caused by susceptible isolates due to: Haemophilus influenzae (in adults) Mycoplasma pneumoniae , Streptococcus pneumoniae , Chlamydophila pneumoniae

1.4 Pharyngitis/Tonsillitis Clarithromycin tablets, USP are indicated for the treatment of mild to moderate infections caused by susceptible isolates due to Streptococcus pyogenes as an alternative in individuals who cannot use first line therapy.

1.5 Uncomplicated Skin and Skin Structure Infections Clarithromycin tablets, USP are indicated for the treatment of mild to moderate infections caused by susceptible isolates due to Staphylococcus aureus , or Streptococcus pyogenes .

1.6 Acute Otitis Media Clarithromycin tablets, USP are indicated in pediatric patients for the treatment of mild to moderate infections caused by susceptible isolates due to Haemophilus influenzae , Moraxella catarrhalis , or Streptococcus pneumoniae [see Clinical Studies (14.2) ] .

1.7 Treatment and Prophylaxis of Disseminated Mycobacterial Infections Clarithromycin tablets, USP are indicated for the treatment of mild to moderate infections caused by susceptible isolates due to Mycobacterium avium or Mycobacterium intracellulare in patients with advanced HIV infection [see Clinical Studies (14.1) ] .

1.8 Helicobacter pylori Infection and Duodenal Ulcer Disease Clarithromycin tablet, USP is given in combination with other drugs in adults as described below to eradicate H. pylori . The eradication of H. pylori has been demonstrated to reduce the risk of duodenal ulcer recurrence [see Clinical Studies (14.3) ] . Clarithromycin tablets, USP in combination with amoxicillin and PREVACID (lansoprazole) or PRILOSEC (omeprazole) Delayed-Release Capsules, as triple therapy, are indicated for the treatment of patients with H. pylori infection and duodenal ulcer disease (active or five-year history of duodenal ulcer) to eradicate H. pylori . Clarithromycin tablets, USP in combination with PRILOSEC (omeprazole) capsules are indicated for the treatment of patients with an active duodenal ulcer associated with H. pylori infection. Regimens which contain clarithromycin tablets, USP as the single antibacterial agent are more likely to be associated with the development of clarithromycin resistance among patients who fail therapy. Clarithromycin-containing regimens should not be used in patients with known or suspected clarithromycin resistant isolates because the efficacy of treatment is reduced in this setting.

1.9 Limitations of Use There is resistance to macrolides in certain bacterial infections caused by Streptococcus pneumoniae and Staphylococcus aureus . Susceptibility testing should be performed when clinically indicated.

1.10 Usage To reduce the development of drug-resistant bacteria and maintain the effectiveness of clarithromycin and other antibacterial drugs, clarithromycin should be used only to treat or prevent infections that are proven or strongly suspected to be caused by susceptible bacteria. When culture and susceptibility information are available, they should be considered in selecting or modifying antibacterial therapy. In the absence of such data, local epidemiology and susceptibility patterns may contribute to the empiric selection of therapy.

1.1 Acute Bacterial Exacerbation of Chronic Bronchitis Clarithromycin tablets, USP are indicated in adults for the treatment of mild to moderate infections caused by susceptible isolates due to Haemophilus influenzae , Haemophilus parainfluenzae , Moraxella catarrhalis , or Streptococcus pneumoniae [see Indications and Usage (1.9) ] .

1.2 Acute Maxillary Sinusitis Clarithromycin tablets, USP are indicated for the treatment of mild to moderate infections caused by susceptible isolates due to Haemophilus influenzae , Moraxella catarrhalis , or Streptococcus pneumoniae [see Indications and Usage (1.9) ] .

1.3 Community-Acquired Pneumonia Clarithromycin tablets, USP are indicated [see Indications and Usage (1.9) ] for the treatment of mild to moderate infections caused by susceptible isolates due to: Haemophilus influenzae (in adults) Mycoplasma pneumoniae , Streptococcus pneumoniae , Chlamydophila pneumoniae

1.4 Pharyngitis/Tonsillitis Clarithromycin tablets, USP are indicated for the treatment of mild to moderate infections caused by susceptible isolates due to Streptococcus pyogenes as an alternative in individuals who cannot use first line therapy.

1.5 Uncomplicated Skin and Skin Structure Infections Clarithromycin tablets, USP are indicated for the treatment of mild to moderate infections caused by susceptible isolates due to Staphylococcus aureus , or Streptococcus pyogenes .

1.6 Acute Otitis Media Clarithromycin tablets, USP are indicated in pediatric patients for the treatment of mild to moderate infections caused by susceptible isolates due to Haemophilus influenzae , Moraxella catarrhalis , or Streptococcus pneumoniae [see Clinical Studies (14.2) ] .

1.7 Treatment and Prophylaxis of Disseminated Mycobacterial Infections Clarithromycin tablets, USP are indicated for the treatment of mild to moderate infections caused by susceptible isolates due to Mycobacterium avium or Mycobacterium intracellulare in patients with advanced HIV infection [see Clinical Studies (14.1) ] .

1.8 Helicobacter pylori Infection and Duodenal Ulcer Disease Clarithromycin tablet, USP is given in combination with other drugs in adults as described below to eradicate H. pylori . The eradication of H. pylori has been demonstrated to reduce the risk of duodenal ulcer recurrence [see Clinical Studies (14.3) ] . Clarithromycin tablets, USP in combination with amoxicillin and PREVACID (lansoprazole) or PRILOSEC (omeprazole) Delayed-Release Capsules, as triple therapy, are indicated for the treatment of patients with H. pylori infection and duodenal ulcer disease (active or five-year history of duodenal ulcer) to eradicate H. pylori . Clarithromycin tablets, USP in combination with PRILOSEC (omeprazole) capsules are indicated for the treatment of patients with an active duodenal ulcer associated with H. pylori infection. Regimens which contain clarithromycin tablets, USP as the single antibacterial agent are more likely to be associated with the development of clarithromycin resistance among patients who fail therapy. Clarithromycin-containing regimens should not be used in patients with known or suspected clarithromycin resistant isolates because the efficacy of treatment is reduced in this setting.

1.9 Limitations of Use There is resistance to macrolides in certain bacterial infections caused by Streptococcus pneumoniae and Staphylococcus aureus . Susceptibility testing should be performed when clinically indicated.

1.10 Usage To reduce the development of drug-resistant bacteria and maintain the effectiveness of clarithromycin and other antibacterial drugs, clarithromycin should be used only to treat or prevent infections that are proven or strongly suspected to be caused by susceptible bacteria. When culture and susceptibility information are available, they should be considered in selecting or modifying antibacterial therapy. In the absence of such data, local epidemiology and susceptibility patterns may contribute to the empiric selection of therapy.

AND ADMINISTRATION Adults: clarithromycin 250 mg or 500 mg every 12 hours for 7–14 days (2.2) Adults: H. pylori eradication (in combination with lansoprazole/amoxicillin, omeprazole/amoxicillin, or omeprazole): clarithromycin 500 mg every 8 or 12 hours for 10–14 days. See full prescribing information (FPI) for additional information. (2.3)

Pediatric

Patients: clarithromycin 15 mg/kg/day divided every 12 hours for 10 days (2.4)

Mycobacterial

Infections: clarithromycin 500 mg every 12 hours; clarithromycin 7.5 mg/kg up to 500 mg every 12 hours in pediatric patients (2.5) Reduce dose in moderate renal impairment with concomitant atazanavir or ritonavir-containing regimens and in severe renal impairment (2.6)

2.1 Important Administration Instructions Clarithromycin tablets may be given with or without food.

2.2 Adult Dosage The recommended dosages of clarithromycin for the treatment of mild to moderate infections in adults are listed in Table 1.

Table

1.

Adult Dosage Guidelines

Clarithromycin tablets Infection Dosage (every 12 hours) Duration (days) Acute bacterial exacerbation of chronic bronchitis 250 to 500 mg a 7 b -14 Acute maxillary sinusitis 500 mg 14 Community-acquired pneumonia 250 mg c 7 d -14 Pharyngitis/Tonsillitis 250 mg 10 Uncomplicated skin and skin structure infections 250 mg 7-14 Treatment and prophylaxis of disseminated Mycobacterium avium disease [see Dosage and Administration (2.5) ] 500 mg e - H.pylori eradication to reduce the risk of duodenal ulcer recurrence with amoxicillin and omeprazole or lansoprazole [see Dosage and Administration (2.3) ] 500 mg 10-14 H.pylori eradication to reduce the risk of duodenal ulcer recurrence with omeprazole [see Dosage and Administration (2.3) ] 500 mg every 8 hours 14 a For M. catarrhalis and S. pneumoniae use 250 mg. For H. influenzae and H. parainfluenzae , use 500 mg. b For H. parainfluenzae , the duration of therapy is 7 days. c For H. parainfluenzae and M. catarrhalis use clarithromycin extended-release tablets only. d For H. influenzae , the duration of therapy is 7 days. e Clarithromycin therapy should continue if clinical response is observed. Clarithromycin can be discontinued when the patient is considered at low risk of disseminated infection.

2.3 Combination Dosing Regimens for H. pylori Infection Triple therapy: clarithromycin/lansoprazole/amoxicillin The recommended adult dosage is 500 mg clarithromycin, 30 mg lansoprazole, and 1 gram amoxicillin, all given every 12 hours for 10 or 14 days [see Indications and Usage (1.8) and Clinical Studies (14.3) ] . Triple therapy: clarithromycin/omeprazole/amoxicillin The recommended adult dosage is 500 mg clarithromycin, 20 mg omeprazole, and 1 gram amoxicillin; all given every 12 hours for 10 days. In patients with an ulcer present at the time of initiation of therapy, an additional 18 days of omeprazole 20 mg once daily is recommended for ulcer healing and symptom relief [see Indications and Usage (1.8) and Clinical Studies (14.3) ] . Dual therapy: clarithromycin/omeprazole The recommended adult dosage is 500 mg clarithromycin given every 8 hours and 40 mg omeprazole given once every morning for 14 days. An additional 14 days of omeprazole 20 mg once daily is recommended for ulcer healing and symptom relief [see Indications and Usage (1.8) and Clinical Studies (14.3) ] .

2.4 Pediatric Dosage The recommended daily dosage is 15 mg/kg/day divided every 12 hours for 10 days (up to the adult dose). Refer to dosage regimens for mycobacterial infections in pediatric patients for additional dosage information [see Dosage and Administration (2.5) ] .

2.5 Dosage Regimens for Mycobacterial Infections For the treatment of disseminated infection due to Mycobacterium avium complex (MAC), clarithromycin is recommended as the primary agents. Clarithromycin should be used in combination with other antimycobacterial drugs (e.g., ethambutol) that have shown in vitro activity against MAC or clinical benefit in MAC treatment [see Clinical Studies (14.1) ] .

Adult Patients

For treatment and prophylaxis of mycobacterial infections in adults, the recommended dose of clarithromycin is 500 mg every 12 hours.

Pediatric Patients

For treatment and prophylaxis of mycobacterial infections in pediatric patients, the recommended dose is 7.5 mg/kg every 12 hours up to 500 mg every 12 hours. [See Use in Specific Populations (8.4) and Clinical Studies (14.1) ] . Clarithromycin therapy should continue if clinical response is observed. Clarithromycin can be discontinued when the patient is considered at low risk of disseminated infection.

2.6 Dosage Adjustment in Patients with Renal Impairment See Table 2 for dosage adjustment in patients with moderate or severe renal impairment with or without concomitant atazanavir or ritonavir-containing regimens [see Drug Interactions (7) ] .

Table

2.

Clarithromycin Dosage

Adjustments in Patients with Renal Impairment Recommended Clarithromycin Dosage Reduction Patients with severe renal impairment (CL cr of <30 mL/min) Reduce the dosage of clarithromycin by 50% Patients with moderate renal impairment (CL cr of 30 to 60 mL/min) taking concomitant atazanavir or ritonavir-containing regimens Reduce the dosage of clarithromycin by 50% Patients with severe renal impairment (CL cr of <30 mL/min) taking concomitant atazanavir or ritonavir-containing regimens Reduce the dosage of clarithromycin by 75%

2.7 Dosage Adjustment Due to Drug Interactions Decrease the dose of clarithromycin by 50% when co-administered with atazanavir [see Drug Interactions (7) ] . Dosage adjustments for other drugs when co-administered with clarithromycin may be recommended due to drug interactions [see Drug Interactions (7) ] .

2.1 Important Administration Instructions Clarithromycin tablets may be given with or without food.

2.2 Adult Dosage The recommended dosages of clarithromycin for the treatment of mild to moderate infections in adults are listed in Table 1.

Table

1.

Adult Dosage Guidelines

Clarithromycin tablets Infection Dosage (every 12 hours) Duration (days) Acute bacterial exacerbation of chronic bronchitis 250 to 500 mg a 7 b -14 Acute maxillary sinusitis 500 mg 14 Community-acquired pneumonia 250 mg c 7 d -14 Pharyngitis/Tonsillitis 250 mg 10 Uncomplicated skin and skin structure infections 250 mg 7-14 Treatment and prophylaxis of disseminated Mycobacterium avium disease [see Dosage and Administration (2.5) ] 500 mg e - H.pylori eradication to reduce the risk of duodenal ulcer recurrence with amoxicillin and omeprazole or lansoprazole [see Dosage and Administration (2.3) ] 500 mg 10-14 H.pylori eradication to reduce the risk of duodenal ulcer recurrence with omeprazole [see Dosage and Administration (2.3) ] 500 mg every 8 hours 14 a For M. catarrhalis and S. pneumoniae use 250 mg. For H. influenzae and H. parainfluenzae , use 500 mg. b For H. parainfluenzae , the duration of therapy is 7 days. c For H. parainfluenzae and M. catarrhalis use clarithromycin extended-release tablets only. d For H. influenzae , the duration of therapy is 7 days. e Clarithromycin therapy should continue if clinical response is observed. Clarithromycin can be discontinued when the patient is considered at low risk of disseminated infection.

2.3 Combination Dosing Regimens for H. pylori Infection Triple therapy: clarithromycin/lansoprazole/amoxicillin The recommended adult dosage is 500 mg clarithromycin, 30 mg lansoprazole, and 1 gram amoxicillin, all given every 12 hours for 10 or 14 days [see Indications and Usage (1.8) and Clinical Studies (14.3) ] . Triple therapy: clarithromycin/omeprazole/amoxicillin The recommended adult dosage is 500 mg clarithromycin, 20 mg omeprazole, and 1 gram amoxicillin; all given every 12 hours for 10 days. In patients with an ulcer present at the time of initiation of therapy, an additional 18 days of omeprazole 20 mg once daily is recommended for ulcer healing and symptom relief [see Indications and Usage (1.8) and Clinical Studies (14.3) ] . Dual therapy: clarithromycin/omeprazole The recommended adult dosage is 500 mg clarithromycin given every 8 hours and 40 mg omeprazole given once every morning for 14 days. An additional 14 days of omeprazole 20 mg once daily is recommended for ulcer healing and symptom relief [see Indications and Usage (1.8) and Clinical Studies (14.3) ] .

2.4 Pediatric Dosage The recommended daily dosage is 15 mg/kg/day divided every 12 hours for 10 days (up to the adult dose). Refer to dosage regimens for mycobacterial infections in pediatric patients for additional dosage information [see Dosage and Administration (2.5) ] .

2.5 Dosage Regimens for Mycobacterial Infections For the treatment of disseminated infection due to Mycobacterium avium complex (MAC), clarithromycin is recommended as the primary agents. Clarithromycin should be used in combination with other antimycobacterial drugs (e.g., ethambutol) that have shown in vitro activity against MAC or clinical benefit in MAC treatment [see Clinical Studies (14.1) ] .

Adult Patients

For treatment and prophylaxis of mycobacterial infections in adults, the recommended dose of clarithromycin is 500 mg every 12 hours.

Pediatric Patients

For treatment and prophylaxis of mycobacterial infections in pediatric patients, the recommended dose is 7.5 mg/kg every 12 hours up to 500 mg every 12 hours. [See Use in Specific Populations (8.4) and Clinical Studies (14.1) ] . Clarithromycin therapy should continue if clinical response is observed. Clarithromycin can be discontinued when the patient is considered at low risk of disseminated infection.

2.6 Dosage Adjustment in Patients with Renal Impairment See Table 2 for dosage adjustment in patients with moderate or severe renal impairment with or without concomitant atazanavir or ritonavir-containing regimens [see Drug Interactions (7) ] .

Table

2.

Clarithromycin Dosage

Adjustments in Patients with Renal Impairment Recommended Clarithromycin Dosage Reduction Patients with severe renal impairment (CL cr of <30 mL/min) Reduce the dosage of clarithromycin by 50% Patients with moderate renal impairment (CL cr of 30 to 60 mL/min) taking concomitant atazanavir or ritonavir-containing regimens Reduce the dosage of clarithromycin by 50% Patients with severe renal impairment (CL cr of <30 mL/min) taking concomitant atazanavir or ritonavir-containing regimens Reduce the dosage of clarithromycin by 75%

2.7 Dosage Adjustment Due to Drug Interactions Decrease the dose of clarithromycin by 50% when co-administered with atazanavir [see Drug Interactions (7) ] . Dosage adjustments for other drugs when co-administered with clarithromycin may be recommended due to drug interactions [see Drug Interactions (7) ] .

Hypersensitivity to clarithromycin or any macrolide drug (4.1) Cisapride and pimozide (4.2) History of cholestatic jaundice/hepatic dysfunction with use of clarithromycin (4.3) Colchicine in renal or hepatic impairment (4.4) Lomitapide, lovastatin, and simvastatin (4.5) Ergot alkaloids (ergotamine or dihydroergotamine) (4.6) Lurasidone (4.7)

4.1 Hypersensitivity Clarithromycin is contraindicated in patients with a known hypersensitivity to clarithromycin, erythromycin, or any of the macrolide antibacterial drugs [see Warnings and Precautions (5.1) ] .

4.2 Cisapride and Pimozide Concomitant administration of clarithromycin with cisapride and pimozide is contraindicated [see Drug Interactions (7) ] . There have been postmarketing reports of drug interactions when clarithromycin is co-administered with cisapride or pimozide, resulting in cardiac arrhythmias (QT prolongation, ventricular tachycardia, ventricular fibrillation, and torsades de pointes ) most likely due to inhibition of metabolism of these drugs by clarithromycin. Fatalities have been reported.

4.3 Cholestatic Jaundice/Hepatic Dysfunction Clarithromycin is contraindicated in patients with a history of cholestatic jaundice or hepatic dysfunction associated with prior use of clarithromycin.

4.4 Colchicine Concomitant administration of clarithromycin and colchicine is contraindicated in patients with renal or hepatic impairment.

4.5 Lomitapide, Lovastatin, and Simvastatin Concomitant administration of clarithromycin with lomitapide is contraindicated due to potential for markedly increased transaminases [see Warnings and Precautions (5.4) and Drug Interactions (7) ] . Concomitant administration of clarithromycin with HMG-CoA reductase inhibitors (statins) that are extensively metabolized by CYP3A4 (lovastatin or simvastatin) is contraindicated, due to the increased risk of myopathy, including rhabdomyolysis [see Warnings and Precautions (5.4) and Drug Interactions (7) ] .

4.6 Ergot Alkaloids Concomitant administration of clarithromycin and ergotamine or dihydroergotamine is contraindicated [see Drug Interactions (7) ] .

4.7 Lurasidone Concomitant administration of clarithromycin and lurasidone is contraindicated since it may result in an increase in lurasidone exposure and the potential for serious adverse reactions [see Drug Interactions (7) ] .

4.8 Contraindications for Co-administered Drugs For information about contraindications of other drugs indicated in combination with clarithromycin, refer to their full prescribing information (contraindications section).

4.1 Hypersensitivity Clarithromycin is contraindicated in patients with a known hypersensitivity to clarithromycin, erythromycin, or any of the macrolide antibacterial drugs [see Warnings and Precautions (5.1) ] .

4.2 Cisapride and Pimozide Concomitant administration of clarithromycin with cisapride and pimozide is contraindicated [see Drug Interactions (7) ] . There have been postmarketing reports of drug interactions when clarithromycin is co-administered with cisapride or pimozide, resulting in cardiac arrhythmias (QT prolongation, ventricular tachycardia, ventricular fibrillation, and torsades de pointes ) most likely due to inhibition of metabolism of these drugs by clarithromycin. Fatalities have been reported.

4.3 Cholestatic Jaundice/Hepatic Dysfunction Clarithromycin is contraindicated in patients with a history of cholestatic jaundice or hepatic dysfunction associated with prior use of clarithromycin.

4.4 Colchicine Concomitant administration of clarithromycin and colchicine is contraindicated in patients with renal or hepatic impairment.

4.5 Lomitapide, Lovastatin, and Simvastatin Concomitant administration of clarithromycin with lomitapide is contraindicated due to potential for markedly increased transaminases [see Warnings and Precautions (5.4) and Drug Interactions (7) ] . Concomitant administration of clarithromycin with HMG-CoA reductase inhibitors (statins) that are extensively metabolized by CYP3A4 (lovastatin or simvastatin) is contraindicated, due to the increased risk of myopathy, including rhabdomyolysis [see Warnings and Precautions (5.4) and Drug Interactions (7) ] .

4.6 Ergot Alkaloids Concomitant administration of clarithromycin and ergotamine or dihydroergotamine is contraindicated [see Drug Interactions (7) ] .

4.7 Lurasidone Concomitant administration of clarithromycin and lurasidone is contraindicated since it may result in an increase in lurasidone exposure and the potential for serious adverse reactions [see Drug Interactions (7) ] .

4.8 Contraindications for Co-administered Drugs For information about contraindications of other drugs indicated in combination with clarithromycin, refer to their full prescribing information (contraindications section).

REACTIONS The following serious adverse reactions are described below and elsewhere in the labeling: Acute Hypersensitivity Reactions [see Warnings and Precautions (5.1) ] QT Prolongation [see Warnings and Precautions (5.2) ] Hepatotoxicity [see Warnings and Precautions (5.3) ]

Serious Adverse Reactions

Due to Concomitant Use with Other Drugs [see Warnings and Precautions (5.4) ] Clostridium difficile Associated Diarrhea [see Warnings and Precautions (5.6) ] Exacerbation of Myasthenia Gravis [see Warnings and Precautions (5.8) ] Most frequent adverse reactions for both adult and pediatric populations in clinical trials: abdominal pain, diarrhea, nausea, vomiting, dysgeusia (6.1) To report SUSPECTED ADVERSE REACTIONS, contact Lannett Company, Inc. at 1-844-834-0530 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

6.1 Clinical Trials Experience Because clinical studies are conducted under widely varying conditions, adverse reaction rates observed in the clinical studies of a drug cannot be directly compared to rates in the clinical studies of another drug and may not reflect the rates observed in practice. Based on pooled data across all indications, the most frequent adverse reactions for both adult and pediatric populations observed in clinical trials are abdominal pain, diarrhea, nausea, vomiting and dysgeusia. Also reported were dyspepsia, liver function test abnormal, anaphylactic reaction, candidiasis, headache, insomnia, and rash. The subsequent subsections list the most common adverse reactions for prophylaxis and treatment of mycobacterial infections and duodenal ulcer associated with H. pylori infection. In general, these profiles are consistent with the pooled data described above. Prophylaxis of Mycobacterial Infections In AIDS patients treated with clarithromycin over long periods of time for prophylaxis against M. avium , it was often difficult to distinguish adverse reactions possibly associated with clarithromycin administration from underlying HIV disease or intercurrent illness. Median duration of treatment was 10.6 months for the clarithromycin group and 8.2 months for the placebo group.

Table

4.

Incidence

Rates (%) of Selected Adverse Reactions a in Immunocompromised Adult Patients Receiving Prophylaxis Against M. avium Complex Body System b Clarithromycin (n=339) % Placebo (n=339) % Adverse Reaction Body as a Whole Abdominal pain 5% 4% Headache 3% 1% Digestive Diarrhea 8% 4% Dyspepsia 4% 3% Flatulence 2% 1% Nausea 11% 7% Vomiting 6% 3% Skin & Appendages Rash 3% 4% Special Senses Taste Perversion 8% c 0.3% a Includes those events possibly or probably related to study drug and excludes concurrent conditions b 2% or greater Adverse Reaction Incidence Rates for either treatment group c Significant higher incidence compared to the placebo-treated group Discontinuation due to adverse reactions occurred in 18% of patients receiving clarithromycin compared to 17% of patients receiving placebo in this trial. Primary reasons for discontinuation in clarithromycin treated patients include headache, nausea, vomiting, depression, and taste perversion. Changes in Laboratory Values Selected laboratory adverse experiences that were reported during therapy in greater than 2% of adult patients treated with clarithromycin in a randomized double-blind clinical trial involving 682 patients are presented in Table 5. In immunocompromised patients receiving prophylaxis against M. avium , evaluations of laboratory values were made by analyzing those values outside the seriously abnormal value (i.e., the extreme high or low limit) for the specified test.

Table

5. Percentage of Patients a Exceeding Extreme Laboratory Values in Patients Receiving Prophylaxis Against M. avium Complex Clarithromycin 500 mg twice a day Placebo WBC Count <1 x 10 9 /L 2/103 (4%) 0/95 SGOT >5 x ULN b 7/196 (4%) 5/208 (2%) SGPT >5 x ULN b 6/217 (3%) 4/232 (2%) a Includes only patients with baseline values within the normal range or borderline high (hematology variables) and within normal range or borderline low (chemistry variables) b ULN= Upper Limit of Normal Treatment of Mycobacterial Infections The adverse reaction profiles for both the 500 mg and 1000 mg twice a day dose regimens were similar. In AIDS patients and other immunocompromised patients treated with the higher doses of clarithromycin over long periods of time for mycobacterial infections, it was often difficult to distinguish adverse reactions possibly associated with clarithromycin administration from underlying signs of HIV disease or intercurrent illness. The following analysis summarizes experience during the first 12 weeks of therapy with clarithromycin. Data are reported separately for trial 1 (randomized, double-blind) and trial 2 (open-labeled, compassionate use) and also combined. Adverse reactions were reported less frequently in trial 2, which may be due in part to differences in monitoring between the two studies. In adult patients receiving clarithromycin 500 mg twice a day, the most frequently reported adverse reactions, considered possibly or possibly related to study drug, with an incidence of 5% or greater, are listed below (Table 6).

Approximately

8% of the patients who received 500 mg twice a day and 12% of the patients who received 1000 mg twice a day discontinued therapy due to drug related adverse reactions during the first 12 weeks of therapy; adverse reactions leading to discontinuation in at least 2 patients included nausea, vomiting, abdominal pain, diarrhea, rash, and asthenia.

Table

6.

Selected

Treatment-Related a Adverse Reaction Incidence Rates (%) in Immunocompromised Adult Patients During the First 12 Weeks of Therapy with 500 mg Twice a Day Clarithromycin Dose Adverse Reaction Trial 1 (n=53)

Trial

2 (n=255) Combined (n=308)

Abdominal Pain

8 2 3 Diarrhea 9 2 3 Flatulence 8 0 1 Headache 8 0 2 Nausea 28 9 12 Rash 9 2 3 Taste Perversion 19 0 4 Vomiting 25 4 8 a Includes those events possibly or probably related to study drug and excludes concurrent conditions A limited number of pediatric AIDS patients have been treated with clarithromycin suspension for mycobacterial infections. The most frequently reported adverse reactions excluding those due to the patient’s concurrent conditions were consistent with those observed in adult patients. Changes in Laboratory Values In the first 12 weeks of starting on clarithromycin 500 mg twice a day, 3% of patients has SGOT increases and 2% of patients has SGPT increases > 5 times the upper limit of normal in trial 2 (469 enrolled adult patients) while trial 1 (154 enrolled patients) had no elevation of transaminases. This includes only patients with baseline values within the normal range or borderline low. Duodenal ulcer associated with H. pylori Infection In clinical trials using combination therapy with clarithromycin plus omeprazole and amoxicillin, no adverse reactions specific to the combination of these drugs have been observed. Adverse reactions that have occurred have been limited to those that have been previously reported with clarithromycin, omeprazole or amoxicillin. The adverse reaction profiles are shown below (Table 7) for four randomized double-blind clinical trials in which patients received the combination of clarithromycin 500 mg three times a day, and omeprazole 40 mg daily for 14 days, followed by omeprazole 20 mg once a day, (three studies) or 40 mg once a day (one study) for an additional 14 days. Of the 346 patients who received the combination, 3.5% of patients discontinued drug due to adverse reactions.

Table

7.

Adverse

Reactions with an Incidence of 3% or Greater Adverse Reaction Clarithromycin + Omeprazole (n=346) % of Patients Omeprazole (n=355) % of Patients Clarithromycin (n=166) % of Patients a Taste Perversion 15 1 16 Nausea 5 1 3 Headache 5 6 9 Diarrhea 4 3 7 Vomiting 4 <1 1 Abdominal Pain 3 2 1 Infection 3 4 2 a Only two of four studies Changes in Laboratory Values Changes in laboratory values with possible clinical significance in patients taking clarithromycin and omeprazole in four randomized double-blind trials in 945 patients are as follows: Hepatic: elevated direct bilirubin <1%; GGT <1%; SGOT (AST) <1%; SGPT (ALT) <1%, Renal: elevated serum creatinine <1%.

Less Frequent Adverse Reactions Observed

During Clinical Trials of Clarithromycin Based on pooled data across all indications, the following adverse reactions were observed in clinical trials with clarithromycin at a rate less than 1%: Blood and Lymphatic System Disorders: Leukopenia, neutropenia, thrombocythemia, eosinophilia Cardiac Disorders: Electrocardiogram QT prolonged, cardiac arrest, atrial fibrillation, extrasystoles, palpitations Ear and Labyrinth Disorders: Vertigo, tinnitus, hearing impaired Gastrointestinal Disorders: Stomatitis, glossitis, esophagitis, gastrooesophageal reflux disease, gastritis, proctalgia, abdominal distension, constipation, dry mouth, eructation, flatulence General Disorders and Administration Site Conditions: Malaise, pyrexia, asthenia, chest pain, chills, fatigue Hepatobiliary Disorders: Cholestasis, hepatitis Immune System Disorders: Hypersensitivity Infections and Infestations: Cellulitis, gastroenteritis, infection, vaginal infection Investigations: Blood bilirubin increased, blood alkaline phosphatase increased, blood lactate dehydrogenase increased, albumin globulin ratio abnormal Metabolism and Nutrition Disorders: Anorexia, decreased appetite Musculoskeletal and Connective Tissue Disorders: Myalgia, muscle spasms, nuchal rigidity Nervous System Disorders: Dizziness, tremor, loss of consciousness, dyskinesia, somnolence Psychiatric Disorders: Anxiety, nervousness Renal and Urinary Disorders: Blood creatinine increased, blood urea increased Respiratory, Thoracic and Mediastinal Disorders: Asthma, epistaxis, pulmonary embolism Skin and Subcutaneous Tissue Disorders: Urticaria, dermatitis bullous, pruritus, hyperhidrosis, rash maculo-papular Gastrointestinal Adverse Reactions In the acute exacerbation of chronic bronchitis and acute maxillary sinusitis studies overall gastrointestinal adverse reactions were reported by a similar proportion of patients taking either clarithromycin tablets or clarithromycin extended-release tablets; however, patients taking clarithromycin extended-release tablets reported significantly less severe gastrointestinal symptoms compared to patients taking clarithromycin tablets. In addition, patients taking clarithromycin extended-release tablets had significantly fewer premature discontinuations for drug-related gastrointestinal or abnormal taste adverse reactions compared to clarithromycin tablets. All-Cause Mortality in Patients with Coronary Artery Disease 1 to 10 Years Following Clarithromycin Exposure In one clinical trial evaluating treatment with clarithromycin on outcomes in patients with coronary artery disease, an increase in risk of all-cause mortality was observed in patients randomized to clarithromycin. Clarithromycin for treatment of coronary artery disease is not an approved indication. Patients were treated with clarithromycin or placebo for 14 days and observed for primary outcome events (e.g., all-cause mortality or non-fatal cardiac events) for several years. 1 A numerically higher number of primary outcome events in patients randomized to receive clarithromycin was observed with a hazard ratio of 1.06 (95% confidence interval 0.98 to 1.14). However, at follow-up 10 years post-treatment, there were 866 (40%) deaths in the clarithromycin group and 815 (37%) deaths in the placebo group that represented a hazard ratio for all-cause mortality of 1.10 (95% confidence interval 1.00 to 1.21). The difference in the number of deaths emerged after one year or more after the end of treatment. The cause of the difference in all-cause mortality has not been established. Other epidemiologic studies evaluating this risk have shown variable results [see Warnings and Precautions (5.5) ] .

6.2 Postmarketing Experience The following adverse reactions have been identified during post-appr use of clarithromycin. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Blood and Lymphatic System: Thrombocytopenia, agranulocytosis Cardiac: Ventricular arrhythmia, ventricular tachycardia, torsades de pointes Ear and Labyrinth: Deafness was reported chiefly in elderly women and was usually reversible. Gastrointestinal: Pancreatitis acute, tongue discoloration, tooth discoloration was reported and was usually reversible with professional cleaning upon discontinuation of the drug. There have been reports of clarithromycin extended-release tablets in the stool, many of which have occurred in patients with anatomic (including ileostomy or colostomy) or functional gastrointestinal disorders with shortened GI transit times. In several reports, tablet residues have occurred in the context of diarrhea. It is recommended that patients who experience tablet residue in the stool and no improvement in their condition should be switched to a different clarithromycin formulation (e.g. suspension) or another antibacterial drug. Hepatobiliary: Hepatic failure, jaundice hepatocellular. Adverse reactions related to hepatic dysfunction have been reported with clarithromycin [see Warnings and Precautions (5.2) ] . Infections and Infestations: Pseudomembranous colitis [see Warnings and Precautions (5.6) ]

Immune

System: Anaphylactic reactions, angioedema Investigations: Prothrombin time prolonged, white blood cell count decreased, international normalized ratio increased. Abnormal urine color has been reported, associated with hepatic failure. Metabolism and Nutrition: Hypoglycemia has been reported in patients taking oral hypoglycemic agents or insulin. Musculoskeletal and Connective Tissue: Myopathy rhabdomyolysis was reported and in some of the reports, clarithromycin was administered concomitantly with statins, fibrates, colchicine or allopurinol [see Contraindications (4.5) and Warnings and Precautions (5.4) ] .

Nervous

System: Parosmia, anosmia, ageusia, paresthesia and convulsions Psychiatric : Abnormal behavior, confusional state, depersonalization, disorientation, hallucination, depression, manic behavior, abnormal dream, psychotic disorder. These disorders usually resolve upon discontinuation of the drug. Renal and Urinary: Nephritis interstitial, renal failure Skin and Subcutaneous Tissue: Stevens-Johnson syndrome, toxic epidermal necrolysis, drug rash with eosinophilia and systemic symptoms (DRESS), Henoch-Schonlein purpura, acne, acute generalized exanthematous pustulosis Vascular: Hemorrhage

6.1 Clinical Trials Experience Because clinical studies are conducted under widely varying conditions, adverse reaction rates observed in the clinical studies of a drug cannot be directly compared to rates in the clinical studies of another drug and may not reflect the rates observed in practice. Based on pooled data across all indications, the most frequent adverse reactions for both adult and pediatric populations observed in clinical trials are abdominal pain, diarrhea, nausea, vomiting and dysgeusia. Also reported were dyspepsia, liver function test abnormal, anaphylactic reaction, candidiasis, headache, insomnia, and rash. The subsequent subsections list the most common adverse reactions for prophylaxis and treatment of mycobacterial infections and duodenal ulcer associated with H. pylori infection. In general, these profiles are consistent with the pooled data described above. Prophylaxis of Mycobacterial Infections In AIDS patients treated with clarithromycin over long periods of time for prophylaxis against M. avium , it was often difficult to distinguish adverse reactions possibly associated with clarithromycin administration from underlying HIV disease or intercurrent illness. Median duration of treatment was 10.6 months for the clarithromycin group and 8.2 months for the placebo group.

Table

4.

Incidence

Rates (%) of Selected Adverse Reactions a in Immunocompromised Adult Patients Receiving Prophylaxis Against M. avium Complex Body System b Clarithromycin (n=339) % Placebo (n=339) % Adverse Reaction Body as a Whole Abdominal pain 5% 4% Headache 3% 1% Digestive Diarrhea 8% 4% Dyspepsia 4% 3% Flatulence 2% 1% Nausea 11% 7% Vomiting 6% 3% Skin & Appendages Rash 3% 4% Special Senses Taste Perversion 8% c 0.3% a Includes those events possibly or probably related to study drug and excludes concurrent conditions b 2% or greater Adverse Reaction Incidence Rates for either treatment group c Significant higher incidence compared to the placebo-treated group Discontinuation due to adverse reactions occurred in 18% of patients receiving clarithromycin compared to 17% of patients receiving placebo in this trial. Primary reasons for discontinuation in clarithromycin treated patients include headache, nausea, vomiting, depression, and taste perversion. Changes in Laboratory Values Selected laboratory adverse experiences that were reported during therapy in greater than 2% of adult patients treated with clarithromycin in a randomized double-blind clinical trial involving 682 patients are presented in Table 5. In immunocompromised patients receiving prophylaxis against M. avium , evaluations of laboratory values were made by analyzing those values outside the seriously abnormal value (i.e., the extreme high or low limit) for the specified test.

Table

5. Percentage of Patients a Exceeding Extreme Laboratory Values in Patients Receiving Prophylaxis Against M. avium Complex Clarithromycin 500 mg twice a day Placebo WBC Count <1 x 10 9 /L 2/103 (4%) 0/95 SGOT >5 x ULN b 7/196 (4%) 5/208 (2%) SGPT >5 x ULN b 6/217 (3%) 4/232 (2%) a Includes only patients with baseline values within the normal range or borderline high (hematology variables) and within normal range or borderline low (chemistry variables) b ULN= Upper Limit of Normal Treatment of Mycobacterial Infections The adverse reaction profiles for both the 500 mg and 1000 mg twice a day dose regimens were similar. In AIDS patients and other immunocompromised patients treated with the higher doses of clarithromycin over long periods of time for mycobacterial infections, it was often difficult to distinguish adverse reactions possibly associated with clarithromycin administration from underlying signs of HIV disease or intercurrent illness. The following analysis summarizes experience during the first 12 weeks of therapy with clarithromycin. Data are reported separately for trial 1 (randomized, double-blind) and trial 2 (open-labeled, compassionate use) and also combined. Adverse reactions were reported less frequently in trial 2, which may be due in part to differences in monitoring between the two studies. In adult patients receiving clarithromycin 500 mg twice a day, the most frequently reported adverse reactions, considered possibly or possibly related to study drug, with an incidence of 5% or greater, are listed below (Table 6).

Approximately

8% of the patients who received 500 mg twice a day and 12% of the patients who received 1000 mg twice a day discontinued therapy due to drug related adverse reactions during the first 12 weeks of therapy; adverse reactions leading to discontinuation in at least 2 patients included nausea, vomiting, abdominal pain, diarrhea, rash, and asthenia.

Table

6.

Selected

Treatment-Related a Adverse Reaction Incidence Rates (%) in Immunocompromised Adult Patients During the First 12 Weeks of Therapy with 500 mg Twice a Day Clarithromycin Dose Adverse Reaction Trial 1 (n=53)

Trial

2 (n=255) Combined (n=308)

Abdominal Pain

8 2 3 Diarrhea 9 2 3 Flatulence 8 0 1 Headache 8 0 2 Nausea 28 9 12 Rash 9 2 3 Taste Perversion 19 0 4 Vomiting 25 4 8 a Includes those events possibly or probably related to study drug and excludes concurrent conditions A limited number of pediatric AIDS patients have been treated with clarithromycin suspension for mycobacterial infections. The most frequently reported adverse reactions excluding those due to the patient’s concurrent conditions were consistent with those observed in adult patients. Changes in Laboratory Values In the first 12 weeks of starting on clarithromycin 500 mg twice a day, 3% of patients has SGOT increases and 2% of patients has SGPT increases > 5 times the upper limit of normal in trial 2 (469 enrolled adult patients) while trial 1 (154 enrolled patients) had no elevation of transaminases. This includes only patients with baseline values within the normal range or borderline low. Duodenal ulcer associated with H. pylori Infection In clinical trials using combination therapy with clarithromycin plus omeprazole and amoxicillin, no adverse reactions specific to the combination of these drugs have been observed. Adverse reactions that have occurred have been limited to those that have been previously reported with clarithromycin, omeprazole or amoxicillin. The adverse reaction profiles are shown below (Table 7) for four randomized double-blind clinical trials in which patients received the combination of clarithromycin 500 mg three times a day, and omeprazole 40 mg daily for 14 days, followed by omeprazole 20 mg once a day, (three studies) or 40 mg once a day (one study) for an additional 14 days. Of the 346 patients who received the combination, 3.5% of patients discontinued drug due to adverse reactions.

Table

7.

Adverse

Reactions with an Incidence of 3% or Greater Adverse Reaction Clarithromycin + Omeprazole (n=346) % of Patients Omeprazole (n=355) % of Patients Clarithromycin (n=166) % of Patients a Taste Perversion 15 1 16 Nausea 5 1 3 Headache 5 6 9 Diarrhea 4 3 7 Vomiting 4 <1 1 Abdominal Pain 3 2 1 Infection 3 4 2 a Only two of four studies Changes in Laboratory Values Changes in laboratory values with possible clinical significance in patients taking clarithromycin and omeprazole in four randomized double-blind trials in 945 patients are as follows: Hepatic: elevated direct bilirubin <1%; GGT <1%; SGOT (AST) <1%; SGPT (ALT) <1%, Renal: elevated serum creatinine <1%.

Less Frequent Adverse Reactions Observed

During Clinical Trials of Clarithromycin Based on pooled data across all indications, the following adverse reactions were observed in clinical trials with clarithromycin at a rate less than 1%: Blood and Lymphatic System Disorders: Leukopenia, neutropenia, thrombocythemia, eosinophilia Cardiac Disorders: Electrocardiogram QT prolonged, cardiac arrest, atrial fibrillation, extrasystoles, palpitations Ear and Labyrinth Disorders: Vertigo, tinnitus, hearing impaired Gastrointestinal Disorders: Stomatitis, glossitis, esophagitis, gastrooesophageal reflux disease, gastritis, proctalgia, abdominal distension, constipation, dry mouth, eructation, flatulence General Disorders and Administration Site Conditions: Malaise, pyrexia, asthenia, chest pain, chills, fatigue Hepatobiliary Disorders: Cholestasis, hepatitis Immune System Disorders: Hypersensitivity Infections and Infestations: Cellulitis, gastroenteritis, infection, vaginal infection Investigations: Blood bilirubin increased, blood alkaline phosphatase increased, blood lactate dehydrogenase increased, albumin globulin ratio abnormal Metabolism and Nutrition Disorders: Anorexia, decreased appetite Musculoskeletal and Connective Tissue Disorders: Myalgia, muscle spasms, nuchal rigidity Nervous System Disorders: Dizziness, tremor, loss of consciousness, dyskinesia, somnolence Psychiatric Disorders: Anxiety, nervousness Renal and Urinary Disorders: Blood creatinine increased, blood urea increased Respiratory, Thoracic and Mediastinal Disorders: Asthma, epistaxis, pulmonary embolism Skin and Subcutaneous Tissue Disorders: Urticaria, dermatitis bullous, pruritus, hyperhidrosis, rash maculo-papular Gastrointestinal Adverse Reactions In the acute exacerbation of chronic bronchitis and acute maxillary sinusitis studies overall gastrointestinal adverse reactions were reported by a similar proportion of patients taking either clarithromycin tablets or clarithromycin extended-release tablets; however, patients taking clarithromycin extended-release tablets reported significantly less severe gastrointestinal symptoms compared to patients taking clarithromycin tablets. In addition, patients taking clarithromycin extended-release tablets had significantly fewer premature discontinuations for drug-related gastrointestinal or abnormal taste adverse reactions compared to clarithromycin tablets. All-Cause Mortality in Patients with Coronary Artery Disease 1 to 10 Years Following Clarithromycin Exposure In one clinical trial evaluating treatment with clarithromycin on outcomes in patients with coronary artery disease, an increase in risk of all-cause mortality was observed in patients randomized to clarithromycin. Clarithromycin for treatment of coronary artery disease is not an approved indication. Patients were treated with clarithromycin or placebo for 14 days and observed for primary outcome events (e.g., all-cause mortality or non-fatal cardiac events) for several years. 1 A numerically higher number of primary outcome events in patients randomized to receive clarithromycin was observed with a hazard ratio of 1.06 (95% confidence interval 0.98 to 1.14). However, at follow-up 10 years post-treatment, there were 866 (40%) deaths in the clarithromycin group and 815 (37%) deaths in the placebo group that represented a hazard ratio for all-cause mortality of 1.10 (95% confidence interval 1.00 to 1.21). The difference in the number of deaths emerged after one year or more after the end of treatment. The cause of the difference in all-cause mortality has not been established. Other epidemiologic studies evaluating this risk have shown variable results [see Warnings and Precautions (5.5) ] .

6.2 Postmarketing Experience The following adverse reactions have been identified during post-appr use of clarithromycin. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Blood and Lymphatic System: Thrombocytopenia, agranulocytosis Cardiac: Ventricular arrhythmia, ventricular tachycardia, torsades de pointes Ear and Labyrinth: Deafness was reported chiefly in elderly women and was usually reversible. Gastrointestinal: Pancreatitis acute, tongue discoloration, tooth discoloration was reported and was usually reversible with professional cleaning upon discontinuation of the drug. There have been reports of clarithromycin extended-release tablets in the stool, many of which have occurred in patients with anatomic (including ileostomy or colostomy) or functional gastrointestinal disorders with shortened GI transit times. In several reports, tablet residues have occurred in the context of diarrhea. It is recommended that patients who experience tablet residue in the stool and no improvement in their condition should be switched to a different clarithromycin formulation (e.g. suspension) or another antibacterial drug. Hepatobiliary: Hepatic failure, jaundice hepatocellular. Adverse reactions related to hepatic dysfunction have been reported with clarithromycin [see Warnings and Precautions (5.2) ] . Infections and Infestations: Pseudomembranous colitis [see Warnings and Precautions (5.6) ]

Immune

System: Anaphylactic reactions, angioedema Investigations: Prothrombin time prolonged, white blood cell count decreased, international normalized ratio increased. Abnormal urine color has been reported, associated with hepatic failure. Metabolism and Nutrition: Hypoglycemia has been reported in patients taking oral hypoglycemic agents or insulin. Musculoskeletal and Connective Tissue: Myopathy rhabdomyolysis was reported and in some of the reports, clarithromycin was administered concomitantly with statins, fibrates, colchicine or allopurinol [see Contraindications (4.5) and Warnings and Precautions (5.4) ] .

Nervous

System: Parosmia, anosmia, ageusia, paresthesia and convulsions Psychiatric : Abnormal behavior, confusional state, depersonalization, disorientation, hallucination, depression, manic behavior, abnormal dream, psychotic disorder. These disorders usually resolve upon discontinuation of the drug. Renal and Urinary: Nephritis interstitial, renal failure Skin and Subcutaneous Tissue: Stevens-Johnson syndrome, toxic epidermal necrolysis, drug rash with eosinophilia and systemic symptoms (DRESS), Henoch-Schonlein purpura, acne, acute generalized exanthematous pustulosis Vascular: Hemorrhage

AND PRECAUTIONS Severe acute hypersensitivity reactions: Discontinue clarithromycin if occurs (5.1) QT prolongation: Avoid clarithromycin in patients with known QT prolongation or receiving drugs known to prolong the QT interval, ventricular arrhythmia (torsade de pointes), hypokalemia/hypomagnesemia, significant bradycardia, or taking Class IA or III antiarrhythmics (5.2) Hepatotoxicity: Discontinue if signs and symptoms of hepatitis occur (5.3) Serious adverse reactions can occur due to drug interactions of clarithromycin with colchicine, some HMG CoA reductase inhibitors, some calcium channel blockers, and other drugs (5.4) Clostridium difficile associated diarrhea (CDAD): Evaluate if diarrhea occurs (5.5) Embryofetal toxicity: Clarithromycin should not be used in pregnant women except in clinical circumstances where no alternative therapy is appropriate (5.6) Exacerbation of myasthenia gravis (5.7)

5.1 Acute Hypersensitivity Reactions In the event of severe acute hypersensitivity reactions, such as anaphylaxis, Stevens-Johnson Syndrome, toxic epidermal necrolysis, drug rash with eosinophilia and systemic symptoms (DRESS), and Henoch-Schonlein purpura, discontinue clarithromycin therapy immediately and institute appropriate treatment.

5.2 QT Prolongation Clarithromycin has been associated with prolongation of the QT interval and infrequent cases of arrhythmia. Cases of torsades de pointes have been spontaneously reported during postmarketing surveillance in patients receiving clarithromycin. Fatalities have been reported. Avoid clarithromycin in the following patients: patients with known prolongation of the QT interval, ventricular cardiac arrhythmia, including torsades de pointes patients receiving drugs known to prolong the QT interval [see also Contraindications (4.2) ] patients with ongoing proarrhythmic conditions such as uncorrected hypokalemia or hypomagnesemia, clinically significant bradycardia and in patients receiving Class IA (quinidine, procainamide) or Class III (dofetilide, amiodarone, sotalol) antiarrhythmic agents. Elderly patients may be more susceptible to drug-associated effects on the QT interval [see Use in Specific Populations (8.5) ] .

5.3 Hepatotoxicity Hepatic dysfunction, including increased liver enzymes, and hepatocellular and/or cholestatic hepatitis, with or without jaundice, has been reported with clarithromycin. This hepatic dysfunction may be severe and is usually reversible. In some instances, hepatic failure with fatal outcome has been reported and generally has been associated with serious underlying diseases and/or concomitant medications. Symptoms of hepatitis can include anorexia, jaundice, dark urine, pruritus, or tender abdomen. Discontinue clarithromycin immediately if signs and symptoms of hepatitis occur.

5.4 Serious Adverse Reactions Due to Concomitant Use with Other Drugs Serious adverse reactions have been reported in patients taking clarithromycin concomitantly with CYP3A4 substrates. These include colchicine toxicity with colchicine; rhabdomyolysis with simvastatin, lovastatin, and atorvastatin; ; hypotension and with calcium channel blockers metabolized by CYP3A4 (e.g., verapamil, amlodipine, diltiazem, ). . Use clarithromycin with caution when administered concurrently with medications that induce the cytochrome CYP3A4 enzyme. The use of clarithromycin with simvastatin, lovastatin, ergotamine, or dihydroergotamine is contraindicated . Drugs metabolized by CYP3A4: Serious adverse reactions have been reported in patients taking clarithromycin concomitantly with CYP3A4 substrates. These include colchicine toxicity with colchicine; rhabdomyolysis with simvastatin, lovastatin, and atorvastatin; hypoglycemia with disopyramide; hypotension and acute kidney injury with calcium channel blockers metabolized by CYP3A4 (e.g., verapamil, amlodipine, diltiazem, nifedipine). Most reports of acute kidney injury with calcium channel blockers metabolized by CYP3A4 involved elderly patients 65 years of age or older. Use clarithromycin with caution when administered concurrently with medications that induce the cytochrome CYP3A4 enzyme. The use of clarithromycin with simvastatin, lovastatin, ergotamine, or dihydroergotamine is contraindicated [see Contraindications (4.5, 4.6) and Drug Interactions (7) ] . Life-threatening and fatal drug interactions have been reported in patients treated with clarithromycin and colchicine. Clarithromycin is a strong CYP3A4 inhibitor and this interaction may occur while using both drugs at their recommended doses. If co-administration of clarithromycin and colchicine is necessary in patients with normal renal and hepatic function, reduce the dose of colchicine. Monitor patients for clinical symptoms of colchicine toxicity. Concomitant administration of clarithromycin and colchicine is contraindicated in patients with renal or hepatic impairment . Colchicine: Life-threatening and fatal drug interactions have been reported in patients treated with clarithromycin and colchicine. Clarithromycin is a strong CYP3A4 inhibitor and this interaction may occur while using both drugs at their recommended doses. If co-administration of clarithromycin and colchicine is necessary in patients with normal renal and hepatic function, reduce the dose of colchicine. Monitor patients for clinical symptoms of colchicine toxicity. Concomitant administration of clarithromycin and colchicine is contraindicated in patients with renal or hepatic impairment [see Contraindications (4.4) and Drug Interactions (7) ] . Concomitant use of clarithromycin with lovastatin or simvastatin is contraindicated as these statins are extensively metabolized by CYP3A4, and concomitant treatment with clarithromycin increases their plasma concentration, which increases the risk of myopathy, including rhabdomyolysis. Cases of rhabdomyolysis have been reported in patients taking clarithromycin concomitantly with these statins. If treatment with clarithromycin cannot be avoided, therapy with lovastatin or simvastatin must be suspended during the course of treatment. HMG-CoA Reductase Inhibitors (statins): Concomitant use of clarithromycin with lovastatin or simvastatin is contraindicated [see Contraindications (4.5) ] as these statins are extensively metabolized by CYP3A4, and concomitant treatment with clarithromycin increases their plasma concentration, which increases the risk of myopathy, including rhabdomyolysis. Cases of rhabdomyolysis have been reported in patients taking clarithromycin concomitantly with these statins. If treatment with clarithromycin cannot be avoided, therapy with lovastatin or simvastatin must be suspended during the course of treatment. Exercise caution when prescribing clarithromycin with atorvastatin or pravastatin. In situations where the concomitant use of clarithromycin with atorvastatin or pravastatin cannot be avoided, atorvastatin dose should not exceed 20 mg daily and pravastatin dose should not exceed 40 mg daily. Use of a statin that is not dependent on CYP3A metabolism (e.g. fluvastatin) can be considered. It is recommended to prescribe the lowest registered dose if concomitant use cannot be avoided.Exercise caution when prescribing clarithromycin with atorvastatin or pravastatin. In situations where the concomitant use of clarithromycin with atorvastatin or pravastatin cannot be avoided, atorvastatin dose should not exceed 20 mg daily and pravastatin dose should not exceed 40 mg daily. Use of a statin that is not dependent on CYP3A metabolism (e.g. fluvastatin) can be considered. It is recommended to prescribe the lowest registered dose if concomitant use cannot be avoided. The concomitant use of clarithromycin and oral hypoglycemic agents and/or insulin can result in significant hypoglycemia. With certain hypoglycemic drugs such as nateglinide, pioglitazone, repaglinide and rosiglitazone, inhibition of CYP3A enzyme by clarithromycin may be involved and could cause hypoglycemia when used concomitantly. Careful monitoring of glucose is recommended .

Oral Hypoglycemic

Agents/Insulin: The concomitant use of clarithromycin and oral hypoglycemic agents and/or insulin can result in significant hypoglycemia. With certain hypoglycemic drugs such as nateglinide, pioglitazone, repaglinide and rosiglitazone, inhibition of CYP3A enzyme by clarithromycin may be involved and could cause hypoglycemia when used concomitantly. Careful monitoring of glucose is recommended [see Drug Interactions (7) ] . Quetiapine: Use quetiapine and clarithromycin concomitantly with caution. Co-administration could result in increased quetiapine exposure and quetiapine related toxicities such as somnolence, orthostatic hypotension, altered state of consciousness, neuroleptic malignant syndrome, and QT prolongation. Refer to quetiapine prescribing information for recommendations on dose reduction if co-administered with CYP3A4 inhibitors such as clarithromycin [see Drug Interactions (7) ] . There is a risk of serious hemorrhage and significant elevations in INR and prothrombin time when clarithromycin is co-administered with warfarin. Monitor INR and prothrombin times frequently while patients are receiving clarithromycin and oral anticoagulants concurrently .

Oral

Anticoagulants: There is a risk of serious hemorrhage and significant elevations in INR and prothrombin time when clarithromycin is co-administered with warfarin. Monitor INR and prothrombin times frequently while patients are receiving clarithromycin and oral anticoagulants concurrently [see Drug Interactions (7) ] . Increased sedation and prolongation of sedation have been reported with concomitant administration of clarithromycin and triazolobenzodiazepines, such as triazolam and midazolam . Benzodiazepines: Increased sedation and prolongation of sedation have been reported with concomitant administration of clarithromycin and triazolobenzodiazepines, such as triazolam and midazolam [see Drug Interactions (7) ] .

5.5 Clostridium difficile Associated Diarrhea Clostridium difficile associated diarrhea (CDAD) has been reported with use of nearly all antibacterial agents, including clarithromycin, and may range in severity from mild diarrhea to fatal colitis. Treatment with antibacterial agents alters the normal flora of the colon leading to overgrowth of C. difficile . C. difficile produces toxins A and B which contribute to the development of CDAD. Hypertoxin producing strains of C. difficile cause increased morbidity and mortality, as these infections can be refractory to antimicrobial therapy and may require colectomy. CDAD must be considered in all patients who present with diarrhea following antibacterial use. Careful medical history is necessary since CDAD has been reported to occur over two months after the administration of antibacterial agents. If CDAD is suspected or confirmed, ongoing antibacterial use not directed against C. difficile may need to be discontinued. Appropriate fluid and electrolyte management, protein supplementation, antibacterial treatment of C. difficile , and surgical evaluation should be instituted as clinically indicated.

5.6 Embryofetal Toxicity Clarithromycin should not be used in pregnant women except in clinical circumstances where no alternative therapy is appropriate. If clarithromycin is used during pregnancy, or if pregnancy occurs while the patient is taking this drug, the patient should be apprised of the potential hazard to the fetus. Clarithromycin has demonstrated adverse effects on pregnancy outcome and/or embryo-fetal development in monkeys, rats, mice, and rabbits at doses that produced plasma levels 2 times to 17 times the serum levels achieved in humans treated at the maximum recommended human doses [see Use in Specific Populations (8.1) ] .

5.7 Exacerbation of Myasthenia Gravis Exacerbation of symptoms of myasthenia gravis and new onset of symptoms of myasthenic syndrome has been reported in patients receiving clarithromycin therapy.

5.8 Development of Drug Resistant Bacteria Prescribing clarithromycin in the absence of a proven or strongly suspected bacterial infection or a prophylactic indication is unlikely to provide benefit to the patient and increases the risk of the development of drug-resistant bacteria.

5.1 Acute Hypersensitivity Reactions In the event of severe acute hypersensitivity reactions, such as anaphylaxis, Stevens-Johnson Syndrome, toxic epidermal necrolysis, drug rash with eosinophilia and systemic symptoms (DRESS), and Henoch-Schonlein purpura, discontinue clarithromycin therapy immediately and institute appropriate treatment.

5.2 QT Prolongation Clarithromycin has been associated with prolongation of the QT interval and infrequent cases of arrhythmia. Cases of torsades de pointes have been spontaneously reported during postmarketing surveillance in patients receiving clarithromycin. Fatalities have been reported. Avoid clarithromycin in the following patients: patients with known prolongation of the QT interval, ventricular cardiac arrhythmia, including torsades de pointes patients receiving drugs known to prolong the QT interval [see also Contraindications (4.2) ] patients with ongoing proarrhythmic conditions such as uncorrected hypokalemia or hypomagnesemia, clinically significant bradycardia and in patients receiving Class IA (quinidine, procainamide) or Class III (dofetilide, amiodarone, sotalol) antiarrhythmic agents. Elderly patients may be more susceptible to drug-associated effects on the QT interval [see Use in Specific Populations (8.5) ] .

5.3 Hepatotoxicity Hepatic dysfunction, including increased liver enzymes, and hepatocellular and/or cholestatic hepatitis, with or without jaundice, has been reported with clarithromycin. This hepatic dysfunction may be severe and is usually reversible. In some instances, hepatic failure with fatal outcome has been reported and generally has been associated with serious underlying diseases and/or concomitant medications. Symptoms of hepatitis can include anorexia, jaundice, dark urine, pruritus, or tender abdomen. Discontinue clarithromycin immediately if signs and symptoms of hepatitis occur.

5.4 Serious Adverse Reactions Due to Concomitant Use with Other Drugs Serious adverse reactions have been reported in patients taking clarithromycin concomitantly with CYP3A4 substrates. These include colchicine toxicity with colchicine; rhabdomyolysis with simvastatin, lovastatin, and atorvastatin; ; hypotension and with calcium channel blockers metabolized by CYP3A4 (e.g., verapamil, amlodipine, diltiazem, ). . Use clarithromycin with caution when administered concurrently with medications that induce the cytochrome CYP3A4 enzyme. The use of clarithromycin with simvastatin, lovastatin, ergotamine, or dihydroergotamine is contraindicated . Drugs metabolized by CYP3A4: Serious adverse reactions have been reported in patients taking clarithromycin concomitantly with CYP3A4 substrates. These include colchicine toxicity with colchicine; rhabdomyolysis with simvastatin, lovastatin, and atorvastatin; hypoglycemia with disopyramide; hypotension and acute kidney injury with calcium channel blockers metabolized by CYP3A4 (e.g., verapamil, amlodipine, diltiazem, nifedipine). Most reports of acute kidney injury with calcium channel blockers metabolized by CYP3A4 involved elderly patients 65 years of age or older. Use clarithromycin with caution when administered concurrently with medications that induce the cytochrome CYP3A4 enzyme. The use of clarithromycin with simvastatin, lovastatin, ergotamine, or dihydroergotamine is contraindicated [see Contraindications (4.5, 4.6) and Drug Interactions (7) ] . Life-threatening and fatal drug interactions have been reported in patients treated with clarithromycin and colchicine. Clarithromycin is a strong CYP3A4 inhibitor and this interaction may occur while using both drugs at their recommended doses. If co-administration of clarithromycin and colchicine is necessary in patients with normal renal and hepatic function, reduce the dose of colchicine. Monitor patients for clinical symptoms of colchicine toxicity. Concomitant administration of clarithromycin and colchicine is contraindicated in patients with renal or hepatic impairment . Colchicine: Life-threatening and fatal drug interactions have been reported in patients treated with clarithromycin and colchicine. Clarithromycin is a strong CYP3A4 inhibitor and this interaction may occur while using both drugs at their recommended doses. If co-administration of clarithromycin and colchicine is necessary in patients with normal renal and hepatic function, reduce the dose of colchicine. Monitor patients for clinical symptoms of colchicine toxicity. Concomitant administration of clarithromycin and colchicine is contraindicated in patients with renal or hepatic impairment [see Contraindications (4.4) and Drug Interactions (7) ] . Concomitant use of clarithromycin with lovastatin or simvastatin is contraindicated as these statins are extensively metabolized by CYP3A4, and concomitant treatment with clarithromycin increases their plasma concentration, which increases the risk of myopathy, including rhabdomyolysis. Cases of rhabdomyolysis have been reported in patients taking clarithromycin concomitantly with these statins. If treatment with clarithromycin cannot be avoided, therapy with lovastatin or simvastatin must be suspended during the course of treatment. HMG-CoA Reductase Inhibitors (statins): Concomitant use of clarithromycin with lovastatin or simvastatin is contraindicated [see Contraindications (4.5) ] as these statins are extensively metabolized by CYP3A4, and concomitant treatment with clarithromycin increases their plasma concentration, which increases the risk of myopathy, including rhabdomyolysis. Cases of rhabdomyolysis have been reported in patients taking clarithromycin concomitantly with these statins. If treatment with clarithromycin cannot be avoided, therapy with lovastatin or simvastatin must be suspended during the course of treatment. Exercise caution when prescribing clarithromycin with atorvastatin or pravastatin. In situations where the concomitant use of clarithromycin with atorvastatin or pravastatin cannot be avoided, atorvastatin dose should not exceed 20 mg daily and pravastatin dose should not exceed 40 mg daily. Use of a statin that is not dependent on CYP3A metabolism (e.g. fluvastatin) can be considered. It is recommended to prescribe the lowest registered dose if concomitant use cannot be avoided.Exercise caution when prescribing clarithromycin with atorvastatin or pravastatin. In situations where the concomitant use of clarithromycin with atorvastatin or pravastatin cannot be avoided, atorvastatin dose should not exceed 20 mg daily and pravastatin dose should not exceed 40 mg daily. Use of a statin that is not dependent on CYP3A metabolism (e.g. fluvastatin) can be considered. It is recommended to prescribe the lowest registered dose if concomitant use cannot be avoided. The concomitant use of clarithromycin and oral hypoglycemic agents and/or insulin can result in significant hypoglycemia. With certain hypoglycemic drugs such as nateglinide, pioglitazone, repaglinide and rosiglitazone, inhibition of CYP3A enzyme by clarithromycin may be involved and could cause hypoglycemia when used concomitantly. Careful monitoring of glucose is recommended .

Oral Hypoglycemic

Agents/Insulin: The concomitant use of clarithromycin and oral hypoglycemic agents and/or insulin can result in significant hypoglycemia. With certain hypoglycemic drugs such as nateglinide, pioglitazone, repaglinide and rosiglitazone, inhibition of CYP3A enzyme by clarithromycin may be involved and could cause hypoglycemia when used concomitantly. Careful monitoring of glucose is recommended [see Drug Interactions (7) ] . Quetiapine: Use quetiapine and clarithromycin concomitantly with caution. Co-administration could result in increased quetiapine exposure and quetiapine related toxicities such as somnolence, orthostatic hypotension, altered state of consciousness, neuroleptic malignant syndrome, and QT prolongation. Refer to quetiapine prescribing information for recommendations on dose reduction if co-administered with CYP3A4 inhibitors such as clarithromycin [see Drug Interactions (7) ] . There is a risk of serious hemorrhage and significant elevations in INR and prothrombin time when clarithromycin is co-administered with warfarin. Monitor INR and prothrombin times frequently while patients are receiving clarithromycin and oral anticoagulants concurrently .

Oral

Anticoagulants: There is a risk of serious hemorrhage and significant elevations in INR and prothrombin time when clarithromycin is co-administered with warfarin. Monitor INR and prothrombin times frequently while patients are receiving clarithromycin and oral anticoagulants concurrently [see Drug Interactions (7) ] . Increased sedation and prolongation of sedation have been reported with concomitant administration of clarithromycin and triazolobenzodiazepines, such as triazolam and midazolam . Benzodiazepines: Increased sedation and prolongation of sedation have been reported with concomitant administration of clarithromycin and triazolobenzodiazepines, such as triazolam and midazolam [see Drug Interactions (7) ] .

5.5 Clostridium difficile Associated Diarrhea Clostridium difficile associated diarrhea (CDAD) has been reported with use of nearly all antibacterial agents, including clarithromycin, and may range in severity from mild diarrhea to fatal colitis. Treatment with antibacterial agents alters the normal flora of the colon leading to overgrowth of C. difficile . C. difficile produces toxins A and B which contribute to the development of CDAD. Hypertoxin producing strains of C. difficile cause increased morbidity and mortality, as these infections can be refractory to antimicrobial therapy and may require colectomy. CDAD must be considered in all patients who present with diarrhea following antibacterial use. Careful medical history is necessary since CDAD has been reported to occur over two months after the administration of antibacterial agents. If CDAD is suspected or confirmed, ongoing antibacterial use not directed against C. difficile may need to be discontinued. Appropriate fluid and electrolyte management, protein supplementation, antibacterial treatment of C. difficile , and surgical evaluation should be instituted as clinically indicated.

5.6 Embryofetal Toxicity Clarithromycin should not be used in pregnant women except in clinical circumstances where no alternative therapy is appropriate. If clarithromycin is used during pregnancy, or if pregnancy occurs while the patient is taking this drug, the patient should be apprised of the potential hazard to the fetus. Clarithromycin has demonstrated adverse effects on pregnancy outcome and/or embryo-fetal development in monkeys, rats, mice, and rabbits at doses that produced plasma levels 2 times to 17 times the serum levels achieved in humans treated at the maximum recommended human doses [see Use in Specific Populations (8.1) ] .

5.7 Exacerbation of Myasthenia Gravis Exacerbation of symptoms of myasthenia gravis and new onset of symptoms of myasthenic syndrome has been reported in patients receiving clarithromycin therapy.

5.8 Development of Drug Resistant Bacteria Prescribing clarithromycin in the absence of a proven or strongly suspected bacterial infection or a prophylactic indication is unlikely to provide benefit to the patient and increases the risk of the development of drug-resistant bacteria.

PRECAUTIONS General Prescribing clarithromycin in the absence of a proven or strongly suspected bacterial infection or a prophylactic indication is unlikely to provide benefit to the patient and increases the risk of the development of drug-resistant bacteria. Clarithromycin is principally excreted via the liver and kidney. Clarithromycin may be administered without dosage adjustment to patients with hepatic impairment and normal renal function. However, in the presence of severe renal impairment with or without coexisting hepatic impairment, decreased dosage or prolonged dosing intervals may be appropriate. Clarithromycin in combination with ranitidine bismuth citrate therapy is not recommended in patients with creatinine clearance less than 25 mL/min (see DOSAGE AND ADMINISTRATION ). Clarithromycin in combination with ranitidine bismuth citrate should not be used in patients with a history of acute porphyria. Exacerbation of symptoms of myasthenia gravis and new onset of symptoms of myasthenic syndrome has been reported in patients receiving clarithromycin therapy. For information about precautions of other drugs indicated in combination with clarithromycin, refer to the PRECAUTIONS section of their package inserts. Information to Patients Patients should be counseled that antibacterial drugs including clarithromycin should only be used to treat bacterial infections. They do not treat viral infections (e.g., the common cold). When clarithromycin is prescribed to treat a bacterial infection, patients should be told that although it is common to feel better early in the course of therapy, the medication should be taken exactly as directed. Skipping doses or not completing the full course of therapy may (1) decrease the effectiveness of the immediate treatment and (2) increase the likelihood that bacteria will develop resistance and will not be treatable by clarithromycin or other antibacterial drugs in the future. Diarrhea is a common problem caused by antibiotics which usually ends when the antibiotic is discontinued. Sometimes after starting treatment with antibiotics, patients can develop watery and bloody stools (with or without stomach cramps and fever) even as late as two or more months after having taken the last dose of the antibiotic. If this occurs, patients should contact their physician as soon as possible. Clarithromycin may interact with some drugs; therefore patients should be advised to report to their doctor the use of any other medications. Clarithromycin tablets can be taken with or without food and can be taken with milk.

Drug Interactions

Clarithromycin use in patients who are receiving theophylline may be associated with an increase of serum theophylline concentrations. Monitoring of serum theophylline concentrations should be considered for patients receiving high doses of theophylline or with baseline concentrations in the upper therapeutic range. In two studies in which theophylline was administered with clarithromycin (a theophylline sustained-release formulation was dosed at either 6.5 mg/kg or 12 mg/kg together with 250 or 500 mg q12h clarithromycin), the steady-state levels of C max , C min , and the area under the serum concentration time curve (AUC) of theophylline increased about 20%. Hypotension, bradyarrhythmias, and lactic acidosis have been observed in patients receiving concurrent verapamil, belonging to the calcium channel blockers drug class. Concomitant administration of single doses of clarithromycin and carbamazepine has been shown to result in increased plasma concentrations of carbamazepine. Blood level monitoring of carbamazepine may be considered. When clarithromycin and terfenadine were coadministered, plasma concentrations of the active acid metabolite of terfenadine were threefold higher, on average, than the values observed when terfenadine was administered alone. The pharmacokinetics of clarithromycin and the 14-OH-clarithromycin were not significantly affected by coadministration of terfenadine once clarithromycin reached steady-state conditions. Concomitant administration of clarithromycin with terfenadine is contraindicated (see CONTRAINDICATIONS ).

Clarithromycin

500 mg every 8 hours was given in combination with omeprazole 40 mg daily to healthy adult subjects. The steady-state plasma concentrations of omeprazole were increased (C max , AUC 0-24 , and t ½ increases of 30%, 89%, and 34%, respectively), by the concomitant administration of clarithromycin. The mean 24-hour gastric pH value was 5.2 when omeprazole was administered alone and 5.7 when coadministered with clarithromycin. Coadministration of clarithromycin with ranitidine bismuth citrate resulted in increased plasma ranitidine concentrations (57%), increased plasma bismuth trough concentrations (48%), and increased 14-hydroxy-clarithromycin plasma concentrations (31%). These effects are clinically insignificant. Simultaneous oral administration of clarithromycin tablets and zidovudine to HIV-infected adult patients may result in decreased steady-state zidovudine concentrations. Following administration of clarithromycin 500 mg tablets twice daily with zidovudine 100 mg every 4 hours, the steady-state zidovudine AUC decreased 12% compared to administration of zidovudine alone (n=4). Individual values ranged from a decrease of 34% to an increase of 14%. When clarithromycin tablets were administered two to four hours prior to zidovudine, the steady-state zidovudine C max increased 100% whereas the AUC was unaffected (n=24). Administration of clarithromycin and zidovudine should be separated by at least two hours. The impact of co-administration of clarithromycin extended-release tablets and zidovudine has not been evaluated. Simultaneous administration of clarithromycin tablets and didanosine to 12 HIV-infected adult patients resulted in no statistically significant change in didanosine pharmacokinetics. Following administration of fluconazole 200 mg daily and clarithromycin 500 mg twice daily to 21 healthy volunteers, the steady-state clarithromycin C min and AUC increased 33% and 18%, respectively. Steady-state concentrations of 14-OH clarithromycin were not significantly affected by concomitant administration of fluconazole. No dosage adjustment of clarithromycin is necessary when co-administered with fluconazole.

Ritonavir

Concomitant administration of clarithromycin and ritonavir (n = 22) resulted in a 77% increase in clarithromycin AUC and a 100% decrease in the AUC of 14-OH clarithromycin. Clarithromycin may be administered without dosage adjustment to patients with normal renal function taking ritonavir. Since concentrations of 14-OH clarithromycin are significantly reduced when clarithromycin is co-administered with ritonavir, alternative antibacterial therapy should be considered for indications other than infections due to Mycobacterium avium complex (see PRECAUTIONS – Drug Interactions ). Doses of clarithromycin greater than 1000 mg per day should not be co-administered with protease inhibitors. Spontaneous reports in the post-marketing period suggest that concomitant administration of clarithromycin and oral anticoagulants may potentiate the effects of the oral anticoagulants. Prothrombin times should be carefully monitored while patients are receiving clarithromycin and oral anticoagulants simultaneously. Digoxin is a substrate for P-glycoprotein (Pgp) and clarithromycin is known to inhibit Pgp. When clarithromycin and digoxin are co-administered, inhibition of Pgp by clarithromycin may lead to increased exposure of digoxin. Elevated digoxin serum concentrations in patients receiving clarithromycin and digoxin concomitantly have been reported in post-marketing surveillance. Some patients have shown clinical signs consistent with digoxin toxicity, including potentially fatal arrhythmias. Monitoring of serum digoxin concentrations should be considered, especially for patients with digoxin concentrations in the upper therapeutic range. Co-administration of clarithromycin, known to inhibit CYP3A, and a drug primarily metabolized by CYP3A may be associated with elevations in drug concentrations that could increase or prolong both therapeutic and adverse effects of the concomitant drug. Clarithromycin should be used with caution in patients receiving treatment with other drugs known to be CYP3A enzyme substrates, especially if the CYP3A substrate has a narrow safety margin (e.g., carbamazepine) and/or the substrate is extensively metabolized by this enzyme. Dosage adjustments may be considered, and when possible, serum concentrations of drugs primarily metabolized by CYP3A should be monitored closely in patients concurrently receiving clarithromycin. The following are examples of some clinically significant CYP3A based drug interactions. Interactions with other drugs metabolized by the CYP3A isoform are also possible. Carbamazepine and Terfenadine Increased serum concentrations of carbamazepine and the active acid metabolite of terfenadine were observed in clinical trials with clarithromycin.

Colchicine

Colchicine is a substrate for both CYP3A and the efflux transporter, P-glycoprotein (Pgp). Clarithromycin and other macrolides are known to inhibit CYP3A and Pgp. When a single dose of colchicine 0.6 mg was administered with clarithromycin 250 mg BID for 7 days, the colchicine C max increased 197% and the AUC 0-∞ increased 239% compared to administration of colchicine alone. The dose of colchicine should be reduced when co-administered with clarithromycin in patients with normal renal and hepatic function. Concomitant use of clarithromycin and colchicine is contraindicated in patients with renal or hepatic impairment (see WARNINGS ). Efavirenz, Nevirapine, Rifampicin, Rifabutin, and Rifapentine Inducers of CYP3A enzymes, such as efavirenz, nevirapine, rifampicin, rifabutin, and rifapentine will increase the metabolism of clarithromycin, thus decreasing plasma concentrations of clarithromycin, while increasing those of 14-OH-clarithromycin. Since the microbiological activities of clarithromycin and 14-OH-clarithromycin are different for different bacteria, the intended therapeutic effect could be impaired during concomitant administration of clarithromycin and enzyme inducers. Alternative antibacterial treatment should be considered when treating patients receiving inducers of CYP3A. Concomitant administration of rifabutin and clarithromycin resulted in an increase in rifabutin, and decrease in clarithromycin serum levels together with an increased risk of uveitis.

Etravirine

Clarithromycin exposure was decreased by etravirine; however, concentrations of the active metabolite, 14-OH-clarithromycin, were increased.

Because

14-OH-clarithromycin has reduced activity against Mycobacterium avium complex (MAC), overall activity against this pathogen may be altered; therefore alternatives to clarithromycin should be considered for the treatment of MAC. Sildenafil, Tadalafil, and Vardenafil Each of these phosphodiesterase inhibitors is primarily metabolized by CYP3A, and CYP3A will be inhibited by concomitant administration of clarithromycin. Co-administration of clarithromycin with sildenafil, tadalafil, or vardenafil will result in increased exposure of these phosphodiesterase inhibitors. Co-administration of these phosphodiesterase inhibitors with clarithromycin is not recommended.

Tolterodine

The primary route of metabolism for tolterodine is via CYP2D6. However, in a subset of the population devoid of CYP2D6, the identified pathway of metabolism is via CYP3A. In this population subset, inhibition of CYP3A results in significantly higher serum concentrations of tolterodine.

Tolterodine

1 mg twice daily is recommended in patients deficient in CYP2D6 activity (poor metabolizers) when co-administered with clarithromycin. Triazolobenzodiazepines (e.g., alprazolam, midazolam, triazolam) When a single dose of midazolam was co-administered with clarithromycin tablets (500 mg twice daily for 7 days), midazolam AUC increased 174% after intravenous administration of midazolam and 600% after oral administration. When oral midazolam is co-administered with clarithromycin, dose adjustments may be necessary and possible prolongation and intensity of effect should be anticipated. Caution and appropriate dose adjustments should be considered when triazolam or alprazolam is co-administered with clarithromycin. For benzodiazepines which are not metabolized by CYP3A (e.g., temazepam, nitrazepam, lorazepam), a clinically important interaction with clarithromycin is unlikely. There have been post-marketing reports of drug interactions and central nervous system (CNS) effects (e.g., somnolence and confusion) with the concomitant use of clarithromycin and triazolam. Monitoring the patient for increased CNS pharmacological effects is suggested.

Atazanavir

Both clarithromycin and atazanavir are substrates and inhibitors of CYP3A, and there is evidence of a bi-directional drug interaction. Following administration of clarithromycin (500 mg twice daily) with atazanavir (400 mg once daily), the clarithromycin AUC increased 94%, the 14-OH clarithromycin AUC decreased 70% and the atazanavir AUC increased 28%. When clarithromycin is co-administered with atazanavir, the dose of clarithromycin should be decreased by 50%. Since concentrations of 14-OH clarithromycin are significantly reduced when clarithromycin is co-administered with atazanavir, alternative antibacterial therapy should be considered for indications other than infections due to Mycobacterium avium complex (see PRECAUTIONS – Drug Interactions ). Doses of clarithromycin greater than 1000 mg per day should not be co-administered with protease inhibitors.

Itraconazole

Both clarithromycin and itraconazole are substrates and inhibitors of CYP3A, potentially leading to a bi-directional drug interaction when administered concomitantly. Clarithromycin may increase the plasma concentrations of itraconazole, while itraconazole may increase the plasma concentrations of clarithromycin. Patients taking itraconazole and clarithromycin concomitantly should be monitored closely for signs or symptoms of increased or prolonged adverse reactions.

Saquinavir

Both clarithromycin and saquinavir are substrates and inhibitors of CYP3A and there is evidence of a bi-directional drug interaction. Following administration of clarithromycin (500 mg bid) and saquinavir (soft gelatin capsules, 1200 mg tid) to 12 healthy volunteers, the steady-state saquinavir AUC and C max increased 177% and 187% respectively compared to administration of saquinavir alone. Clarithromycin AUC and C max increased 45% and 39% respectively, whereas the 14–OH clarithromycin AUC and C max decreased 24% and 34% respectively, compared to administration with clarithromycin alone. No dose adjustment of clarithromycin is necessary when clarithromycin is co-administered with saquinavir in patients with normal renal function. When saquinavir is co-administered with ritonavir, consideration should be given to the potential effects of ritonavir on clarithromycin (refer to interaction between clarithromycin and ritonavir) (see PRECAUTIONS — Drug Interactions ). The following CYP3A based drug interactions have been observed with erythromycin products and/or with clarithromycin in post-marketing experience: Antiarrhythmics There have been post-marketing reports of torsades de pointes occurring with concurrent use of clarithromycin and quinidine or disopyramide. Electrocardiograms should be monitored for QTc prolongation during coadministration of clarithromycin with these drugs. Serum concentrations of these medications should also be monitored. There have been post marketing reports of hypoglycemia with the concomitant administration of clarithromycin and disopyramide. Therefore, blood glucose levels should be monitored during concomitant administration of clarithromycin and disopyramide.

Ergotamine/Dihydroergotamine

Post-marketing reports indicate that coadministration of clarithromycin with ergotamine or dihydroergotamine has been associated with acute ergot toxicity characterized by vasospasm and ischemia of the extremities and other tissues including the central nervous system. Concomitant administration of clarithromycin with ergotamine or dihydroergotamine is contraindicated (see CONTRAINDICATIONS ). Triazolobenziodidiazepines (Such as Triazolam and Alprazolam) and Related Benzodiazepines (Such as Midazolam) Erythromycin has been reported to decrease the clearance of triazolam and midazolam, and thus, may increase the pharmacologic effect of these benzodiazepines. There have been post-marketing reports of drug interactions and CNS effects (e.g., somnolence and confusion) with the concomitant use of clarithromycin and triazolam.

Quetiapine

Quetiapine is a substrate for CYP3A4, which is inhibited by clarithromycin. Co‑administration with clarithromycin could result in increased quetiapine exposure and possible quetiapine related toxicities. There have been post-marketing reports of somnolence, orthostatic hypotension, altered state of consciousness, neuroleptic malignant syndrome, and QT prolongation during concomitant administration. Refer to quetiapine prescribing information for recommendations on dose reduction if co-administered with CYP3A4 inhibitors such as clarithromycin. Sildenafil (Viagra) Erythromycin has been reported to increase the systemic exposure (AUC) of sildenafil. A similar interaction may occur with clarithromycin; reduction of sildenafil dosage should be considered (see Viagra package insert). There have been spontaneous or published reports of CYP3A based interactions of erythromycin and/or clarithromycin with cyclosporine, carbamazepine, tacrolimus, alfentanil, disopyramide, rifabutin, quinidine, methylprednisolone, cilostazol, bromocriptine, vinblastine, phenobarbital and St. John’s Wort. Concomitant administration of clarithromycin with cisapride, pimozide, astemizole, or terfenadine is contraindicated (see CONTRAINDICATIONS ). In addition, there have been reports of interactions of erythromycin or clarithromycin with drugs not thought to be metabolized by CYP3A, including hexobarbital, phenytoin, and valproate. Carcinogenesis, Mutagenesis, Impairment of Fertility The following in vitro mutagenicity tests have been conducted with clarithromycin: Salmonella /Mammalian Microsomes Test Bacterial Induced Mutation Frequency Test In Vitro Chromosome Aberration Test Rat Hepatocyte DNA Synthesis Assay Mouse Lymphoma Assay Mouse Dominant Lethal Study Mouse Micronucleus Test All tests had negative results except the In Vitro Chromosome Aberration Test which was weakly positive in one test and negative in another. In addition, a Bacterial Reverse-Mutation Test (Ames Test) has been performed on clarithromycin metabolites with negative results. Fertility and reproduction studies have shown that daily doses of up to 160 mg/kg/day (1.3 times the recommended maximum human dose based on mg/m 2 ) to male and female rats caused no adverse effects on the estrous cycle, fertility, parturition, or number and viability of offspring. Plasma levels in rats after 150 mg/kg/day were 2 times the human serum levels. In the 150 mg/kg/day monkey studies, plasma levels were 3 times the human serum levels. When given orally at 150 mg/kg/day (2.4 times the recommended maximum human dose based on mg/m 2 ), clarithromycin was shown to produce embryonic loss in monkeys. This effect has been attributed to marked maternal toxicity of the drug at this high dose. In rabbits, in utero fetal loss occurred at an intravenous dose of 33 mg/m 2 , which is 17 times less than the maximum proposed human oral daily dose of 618 mg/m 2 . Long-term studies in animals have not been performed to evaluate the carcinogenic potential of clarithromycin.

Pregnancy Teratogenic Effects Pregnancy

Category C Four teratogenicity studies in rats (three with oral doses and one with intravenous doses up to 160 mg/kg/day administered during the period of major organogenesis) and two in rabbits at oral doses up to 125 mg/kg/day (approximately 2 times the recommended maximum human dose based on mg/m 2 ) or intravenous doses of 30 mg/kg/day administered during gestation days 6 to 18 failed to demonstrate any teratogenicity from clarithromycin. Two additional oral studies in a different rat strain at similar doses and similar conditions demonstrated a low incidence of cardiovascular anomalies at doses of 150 mg/kg/day administered during gestation days 6 to 15. Plasma levels after 150 mg/kg/day were 2 times the human serum levels. Four studies in mice revealed a variable incidence of cleft palate following oral doses of 1000 mg/kg/day (2 and 4 times the recommended maximum human dose based on mg/m 2 , respectively) during gestation days 6 to 15. Cleft palate was also seen at 500 mg/kg/day.

The

1000 mg/kg/day exposure resulted in plasma levels 17 times the human serum levels. In monkeys, an oral dose of 70 mg/kg/day (an approximate equidose of the recommended maximum human dose based on mg/m 2 ) produced fetal growth retardation at plasma levels that were 2 times the human serum levels. There are no adequate and well-controlled studies in pregnant women. Clarithromycin should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus (see WARNINGS ).

Nursing Mothers

Clarithromycin and its active metabolite 14-hydroxy clarithromycin are excreted in human milk. Serum and milk samples were obtained after 3 days of treatment, at steady state, from one published study of 12 lactating women who were taking clarithromycin 250 mg orally twice daily. Based on the limited data from this study, and assuming milk consumption of 150 mL/kg/day, an exclusively human milk fed infant would receive an estimated average of 136 mcg/kg/day of clarithromycin and its active metabolite, with this maternal dosage regimen. This is less than 2% of the maternal weight-adjusted dose (7.8 mg/kg/day, based on the average maternal weight of 64 kg), and less than 1% of the pediatric dose (15 mg/kg/day) for children greater than 6 months of age. A prospective observational study of 55 breastfed infants of mothers taking a macrolide antibiotic (6 were exposed to clarithromycin) were compared to 36 breastfed infants of mothers taking amoxicillin. Adverse reactions were comparable in both groups. Adverse reactions occurred in 12.7% of infants exposed to macrolides and included rash, diarrhea, loss of appetite, and somnolence. Caution should be exercised when clarithromycin is administered to nursing women. The development and health benefits of human milk feeding should be considered along with the mother’s clinical need for clarithromycin and any potential adverse effects on the human milk fed child from the drug or from the underlying maternal condition.

Pediatric Use

Safety and effectiveness of clarithromycin in pediatric patients under 6 months of age have not been established. The safety of clarithromycin has not been studied in MAC patients under the age of 20 months. Neonatal and juvenile animals tolerated clarithromycin in a manner similar to adult animals. Young animals were slightly more intolerant to acute overdosage and to subtle reductions in erythrocytes, platelets and leukocytes but were less sensitive to toxicity in the liver, kidney, thymus, and genitalia.

Geriatric

Use In a steady-state study in which healthy elderly subjects (age 65 to 81 years old) were given 500 mg every 12 hours, the maximum serum concentrations and area under the curves of clarithromycin and 14-OH clarithromycin were increased compared to those achieved in healthy young adults. These changes in pharmacokinetics parallel known age-related decreases in renal function. In clinical trials, elderly patients did not have an increased incidence of adverse events when compared to younger patients. Dosage adjustment should be considered in elderly patients with severe renal impairment. Elderly patients may be more susceptible to development of torsades de pointes arrhythmias than younger patients (see WARNINGS and PRECAUTIONS ). Most reports of acute kidney injury with calcium channel blockers metabolized by CYP3A4 (e.g., verapamil, amlodipine, diltiazem, nifedipine) involved elderly patients 65 years of age or older (see WARNINGS ).

Drug Interactions Clarithromycin use in patients who are receiving theophylline may be associated with an increase of serum theophylline concentrations. Monitoring of serum theophylline concentrations should be considered for patients receiving high doses of theophylline or with baseline concentrations in the upper therapeutic range. In two studies in which theophylline was administered with clarithromycin (a theophylline sustained-release formulation was dosed at either 6.5 mg/kg or 12 mg/kg together with 250 or 500 mg q12h clarithromycin), the steady-state levels of C max , C min , and the area under the serum concentration time curve (AUC) of theophylline increased about 20%. Hypotension, bradyarrhythmias, and lactic acidosis have been observed in patients receiving concurrent verapamil, belonging to the calcium channel blockers drug class. Concomitant administration of single doses of clarithromycin and carbamazepine has been shown to result in increased plasma concentrations of carbamazepine. Blood level monitoring of carbamazepine may be considered. When clarithromycin and terfenadine were coadministered, plasma concentrations of the active acid metabolite of terfenadine were threefold higher, on average, than the values observed when terfenadine was administered alone. The pharmacokinetics of clarithromycin and the 14-OH-clarithromycin were not significantly affected by coadministration of terfenadine once clarithromycin reached steady-state conditions. Concomitant administration of clarithromycin with terfenadine is contraindicated (see CONTRAINDICATIONS ).

Clarithromycin

500 mg every 8 hours was given in combination with omeprazole 40 mg daily to healthy adult subjects. The steady-state plasma concentrations of omeprazole were increased (C max , AUC 0-24 , and t ½ increases of 30%, 89%, and 34%, respectively), by the concomitant administration of clarithromycin. The mean 24-hour gastric pH value was 5.2 when omeprazole was administered alone and 5.7 when coadministered with clarithromycin. Coadministration of clarithromycin with ranitidine bismuth citrate resulted in increased plasma ranitidine concentrations (57%), increased plasma bismuth trough concentrations (48%), and increased 14-hydroxy-clarithromycin plasma concentrations (31%). These effects are clinically insignificant. Simultaneous oral administration of clarithromycin tablets and zidovudine to HIV-infected adult patients may result in decreased steady-state zidovudine concentrations. Following administration of clarithromycin 500 mg tablets twice daily with zidovudine 100 mg every 4 hours, the steady-state zidovudine AUC decreased 12% compared to administration of zidovudine alone (n=4). Individual values ranged from a decrease of 34% to an increase of 14%. When clarithromycin tablets were administered two to four hours prior to zidovudine, the steady-state zidovudine C max increased 100% whereas the AUC was unaffected (n=24). Administration of clarithromycin and zidovudine should be separated by at least two hours. The impact of co-administration of clarithromycin extended-release tablets and zidovudine has not been evaluated. Simultaneous administration of clarithromycin tablets and didanosine to 12 HIV-infected adult patients resulted in no statistically significant change in didanosine pharmacokinetics. Following administration of fluconazole 200 mg daily and clarithromycin 500 mg twice daily to 21 healthy volunteers, the steady-state clarithromycin C min and AUC increased 33% and 18%, respectively. Steady-state concentrations of 14-OH clarithromycin were not significantly affected by concomitant administration of fluconazole. No dosage adjustment of clarithromycin is necessary when co-administered with fluconazole.

Ritonavir

Concomitant administration of clarithromycin and ritonavir (n = 22) resulted in a 77% increase in clarithromycin AUC and a 100% decrease in the AUC of 14-OH clarithromycin. Clarithromycin may be administered without dosage adjustment to patients with normal renal function taking ritonavir. Since concentrations of 14-OH clarithromycin are significantly reduced when clarithromycin is co-administered with ritonavir, alternative antibacterial therapy should be considered for indications other than infections due to Mycobacterium avium complex (see PRECAUTIONS – Drug Interactions ). Doses of clarithromycin greater than 1000 mg per day should not be co-administered with protease inhibitors. Spontaneous reports in the post-marketing period suggest that concomitant administration of clarithromycin and oral anticoagulants may potentiate the effects of the oral anticoagulants. Prothrombin times should be carefully monitored while patients are receiving clarithromycin and oral anticoagulants simultaneously. Digoxin is a substrate for P-glycoprotein (Pgp) and clarithromycin is known to inhibit Pgp. When clarithromycin and digoxin are co-administered, inhibition of Pgp by clarithromycin may lead to increased exposure of digoxin. Elevated digoxin serum concentrations in patients receiving clarithromycin and digoxin concomitantly have been reported in post-marketing surveillance. Some patients have shown clinical signs consistent with digoxin toxicity, including potentially fatal arrhythmias. Monitoring of serum digoxin concentrations should be considered, especially for patients with digoxin concentrations in the upper therapeutic range. Co-administration of clarithromycin, known to inhibit CYP3A, and a drug primarily metabolized by CYP3A may be associated with elevations in drug concentrations that could increase or prolong both therapeutic and adverse effects of the concomitant drug. Clarithromycin should be used with caution in patients receiving treatment with other drugs known to be CYP3A enzyme substrates, especially if the CYP3A substrate has a narrow safety margin (e.g., carbamazepine) and/or the substrate is extensively metabolized by this enzyme. Dosage adjustments may be considered, and when possible, serum concentrations of drugs primarily metabolized by CYP3A should be monitored closely in patients concurrently receiving clarithromycin. The following are examples of some clinically significant CYP3A based drug interactions. Interactions with other drugs metabolized by the CYP3A isoform are also possible. Carbamazepine and Terfenadine Increased serum concentrations of carbamazepine and the active acid metabolite of terfenadine were observed in clinical trials with clarithromycin.

Colchicine

Colchicine is a substrate for both CYP3A and the efflux transporter, P-glycoprotein (Pgp). Clarithromycin and other macrolides are known to inhibit CYP3A and Pgp. When a single dose of colchicine 0.6 mg was administered with clarithromycin 250 mg BID for 7 days, the colchicine C max increased 197% and the AUC 0-∞ increased 239% compared to administration of colchicine alone. The dose of colchicine should be reduced when co-administered with clarithromycin in patients with normal renal and hepatic function. Concomitant use of clarithromycin and colchicine is contraindicated in patients with renal or hepatic impairment (see WARNINGS ). Efavirenz, Nevirapine, Rifampicin, Rifabutin, and Rifapentine Inducers of CYP3A enzymes, such as efavirenz, nevirapine, rifampicin, rifabutin, and rifapentine will increase the metabolism of clarithromycin, thus decreasing plasma concentrations of clarithromycin, while increasing those of 14-OH-clarithromycin. Since the microbiological activities of clarithromycin and 14-OH-clarithromycin are different for different bacteria, the intended therapeutic effect could be impaired during concomitant administration of clarithromycin and enzyme inducers. Alternative antibacterial treatment should be considered when treating patients receiving inducers of CYP3A. Concomitant administration of rifabutin and clarithromycin resulted in an increase in rifabutin, and decrease in clarithromycin serum levels together with an increased risk of uveitis.

Etravirine

Clarithromycin exposure was decreased by etravirine; however, concentrations of the active metabolite, 14-OH-clarithromycin, were increased.

Because

14-OH-clarithromycin has reduced activity against Mycobacterium avium complex (MAC), overall activity against this pathogen may be altered; therefore alternatives to clarithromycin should be considered for the treatment of MAC. Sildenafil, Tadalafil, and Vardenafil Each of these phosphodiesterase inhibitors is primarily metabolized by CYP3A, and CYP3A will be inhibited by concomitant administration of clarithromycin. Co-administration of clarithromycin with sildenafil, tadalafil, or vardenafil will result in increased exposure of these phosphodiesterase inhibitors. Co-administration of these phosphodiesterase inhibitors with clarithromycin is not recommended.

Tolterodine

The primary route of metabolism for tolterodine is via CYP2D6. However, in a subset of the population devoid of CYP2D6, the identified pathway of metabolism is via CYP3A. In this population subset, inhibition of CYP3A results in significantly higher serum concentrations of tolterodine.

Tolterodine

1 mg twice daily is recommended in patients deficient in CYP2D6 activity (poor metabolizers) when co-administered with clarithromycin. Triazolobenzodiazepines (e.g., alprazolam, midazolam, triazolam) When a single dose of midazolam was co-administered with clarithromycin tablets (500 mg twice daily for 7 days), midazolam AUC increased 174% after intravenous administration of midazolam and 600% after oral administration. When oral midazolam is co-administered with clarithromycin, dose adjustments may be necessary and possible prolongation and intensity of effect should be anticipated. Caution and appropriate dose adjustments should be considered when triazolam or alprazolam is co-administered with clarithromycin. For benzodiazepines which are not metabolized by CYP3A (e.g., temazepam, nitrazepam, lorazepam), a clinically important interaction with clarithromycin is unlikely. There have been post-marketing reports of drug interactions and central nervous system (CNS) effects (e.g., somnolence and confusion) with the concomitant use of clarithromycin and triazolam. Monitoring the patient for increased CNS pharmacological effects is suggested.

Atazanavir

Both clarithromycin and atazanavir are substrates and inhibitors of CYP3A, and there is evidence of a bi-directional drug interaction. Following administration of clarithromycin (500 mg twice daily) with atazanavir (400 mg once daily), the clarithromycin AUC increased 94%, the 14-OH clarithromycin AUC decreased 70% and the atazanavir AUC increased 28%. When clarithromycin is co-administered with atazanavir, the dose of clarithromycin should be decreased by 50%. Since concentrations of 14-OH clarithromycin are significantly reduced when clarithromycin is co-administered with atazanavir, alternative antibacterial therapy should be considered for indications other than infections due to Mycobacterium avium complex (see PRECAUTIONS – Drug Interactions ). Doses of clarithromycin greater than 1000 mg per day should not be co-administered with protease inhibitors.

Itraconazole

Both clarithromycin and itraconazole are substrates and inhibitors of CYP3A, potentially leading to a bi-directional drug interaction when administered concomitantly. Clarithromycin may increase the plasma concentrations of itraconazole, while itraconazole may increase the plasma concentrations of clarithromycin. Patients taking itraconazole and clarithromycin concomitantly should be monitored closely for signs or symptoms of increased or prolonged adverse reactions.

Saquinavir

Both clarithromycin and saquinavir are substrates and inhibitors of CYP3A and there is evidence of a bi-directional drug interaction. Following administration of clarithromycin (500 mg bid) and saquinavir (soft gelatin capsules, 1200 mg tid) to 12 healthy volunteers, the steady-state saquinavir AUC and C max increased 177% and 187% respectively compared to administration of saquinavir alone. Clarithromycin AUC and C max increased 45% and 39% respectively, whereas the 14–OH clarithromycin AUC and C max decreased 24% and 34% respectively, compared to administration with clarithromycin alone. No dose adjustment of clarithromycin is necessary when clarithromycin is co-administered with saquinavir in patients with normal renal function. When saquinavir is co-administered with ritonavir, consideration should be given to the potential effects of ritonavir on clarithromycin (refer to interaction between clarithromycin and ritonavir) (see PRECAUTIONS — Drug Interactions ). The following CYP3A based drug interactions have been observed with erythromycin products and/or with clarithromycin in post-marketing experience: Antiarrhythmics There have been post-marketing reports of torsades de pointes occurring with concurrent use of clarithromycin and quinidine or disopyramide. Electrocardiograms should be monitored for QTc prolongation during coadministration of clarithromycin with these drugs. Serum concentrations of these medications should also be monitored. There have been post marketing reports of hypoglycemia with the concomitant administration of clarithromycin and disopyramide. Therefore, blood glucose levels should be monitored during concomitant administration of clarithromycin and disopyramide.

Ergotamine/Dihydroergotamine

Post-marketing reports indicate that coadministration of clarithromycin with ergotamine or dihydroergotamine has been associated with acute ergot toxicity characterized by vasospasm and ischemia of the extremities and other tissues including the central nervous system. Concomitant administration of clarithromycin with ergotamine or dihydroergotamine is contraindicated (see CONTRAINDICATIONS ). Triazolobenziodidiazepines (Such as Triazolam and Alprazolam) and Related Benzodiazepines (Such as Midazolam) Erythromycin has been reported to decrease the clearance of triazolam and midazolam, and thus, may increase the pharmacologic effect of these benzodiazepines. There have been post-marketing reports of drug interactions and CNS effects (e.g., somnolence and confusion) with the concomitant use of clarithromycin and triazolam.

Quetiapine

Quetiapine is a substrate for CYP3A4, which is inhibited by clarithromycin. Co‑administration with clarithromycin could result in increased quetiapine exposure and possible quetiapine related toxicities. There have been post-marketing reports of somnolence, orthostatic hypotension, altered state of consciousness, neuroleptic malignant syndrome, and QT prolongation during concomitant administration. Refer to quetiapine prescribing information for recommendations on dose reduction if co-administered with CYP3A4 inhibitors such as clarithromycin. Sildenafil (Viagra) Erythromycin has been reported to increase the systemic exposure (AUC) of sildenafil. A similar interaction may occur with clarithromycin; reduction of sildenafil dosage should be considered (see Viagra package insert). There have been spontaneous or published reports of CYP3A based interactions of erythromycin and/or clarithromycin with cyclosporine, carbamazepine, tacrolimus, alfentanil, disopyramide, rifabutin, quinidine, methylprednisolone, cilostazol, bromocriptine, vinblastine, phenobarbital and St. John’s Wort. Concomitant administration of clarithromycin with cisapride, pimozide, astemizole, or terfenadine is contraindicated (see CONTRAINDICATIONS ). In addition, there have been reports of interactions of erythromycin or clarithromycin with drugs not thought to be metabolized by CYP3A, including hexobarbital, phenytoin, and valproate.

Ritonavir

Concomitant administration of clarithromycin and ritonavir (n = 22) resulted in a 77% increase in clarithromycin AUC and a 100% decrease in the AUC of 14-OH clarithromycin. Clarithromycin may be administered without dosage adjustment to patients with normal renal function taking ritonavir. Since concentrations of 14-OH clarithromycin are significantly reduced when clarithromycin is co-administered with ritonavir, alternative antibacterial therapy should be considered for indications other than infections due to Mycobacterium avium complex (see PRECAUTIONS – Drug Interactions ). Doses of clarithromycin greater than 1000 mg per day should not be co-administered with protease inhibitors. Spontaneous reports in the post-marketing period suggest that concomitant administration of clarithromycin and oral anticoagulants may potentiate the effects of the oral anticoagulants. Prothrombin times should be carefully monitored while patients are receiving clarithromycin and oral anticoagulants simultaneously. Digoxin is a substrate for P-glycoprotein (Pgp) and clarithromycin is known to inhibit Pgp. When clarithromycin and digoxin are co-administered, inhibition of Pgp by clarithromycin may lead to increased exposure of digoxin. Elevated digoxin serum concentrations in patients receiving clarithromycin and digoxin concomitantly have been reported in post-marketing surveillance. Some patients have shown clinical signs consistent with digoxin toxicity, including potentially fatal arrhythmias. Monitoring of serum digoxin concentrations should be considered, especially for patients with digoxin concentrations in the upper therapeutic range. Co-administration of clarithromycin, known to inhibit CYP3A, and a drug primarily metabolized by CYP3A may be associated with elevations in drug concentrations that could increase or prolong both therapeutic and adverse effects of the concomitant drug. Clarithromycin should be used with caution in patients receiving treatment with other drugs known to be CYP3A enzyme substrates, especially if the CYP3A substrate has a narrow safety margin (e.g., carbamazepine) and/or the substrate is extensively metabolized by this enzyme. Dosage adjustments may be considered, and when possible, serum concentrations of drugs primarily metabolized by CYP3A should be monitored closely in patients concurrently receiving clarithromycin. The following are examples of some clinically significant CYP3A based drug interactions. Interactions with other drugs metabolized by the CYP3A isoform are also possible.

Side Effect	Reports	% of Total	Deaths	Hosp.
Drug ineffective	2,012	10.6%	187	808
Nausea	1,597	8.4%	40	656
Drug hypersensitivity	1,558	8.2%	13	221
Drug interaction	1,288	6.8%	105	789
Diarrhoea	1,228	6.5%	22	385
Dyspnoea	1,151	6.1%	69	496
Malaise	1,131	6.0%	48	569
Headache	1,047	5.5%	14	386
Off label use	944	5.0%	59	490
Vomiting	921	4.9%	29	428
Pyrexia	802	4.2%	56	555
Macular degeneration	791	4.2%	0	232
Rash	784	4.1%	35	298
Dizziness	731	3.9%	10	230
Dysgeusia	717	3.8%	7	65
Abdominal pain	699	3.7%	7	365
Hypersensitivity	664	3.5%	2	146
Abdominal pain upper	656	3.5%	15	203
Erythema	623	3.3%	10	361
Insomnia	618	3.3%	7	160

Year	Reports	Deaths	Hosp.
2000	17	0	8
2001	11	1	7
2002	3	2	3
2003	16	0	14
2004	22	16	5
2005	6	1	2
2006	27	0	24
2007	21	2	13
2008	42	0	33
2009	42	3	24
2010	41	11	25
2011	80	17	55
2012	106	5	60
2013	207	31	119
2014	853	32	371
2015	937	45	359
2016	899	24	373
2017	1,001	38	375
2018	1,142	65	402
2019	992	18	380
2020	687	27	243
2021	687	57	174
2022	467	21	135
2023	432	6	155
2024	365	2	88
2025	169	3	49

Indication	Reports
Product used for unknown indication	5,816
Helicobacter infection	1,529
Lower respiratory tract infection	878
Pneumonia	853
Bronchitis	389
Mycobacterium avium complex infection	387
Sinusitis	348
Helicobacter gastritis	294
Infection	294
Mycobacterial infection	278

CLARITHROMYCIN: 18,945 Adverse Event Reports & Safety Profile

What Are the Most Common CLARITHROMYCIN Side Effects?

All CLARITHROMYCIN Side Effects by Frequency

Who Reports CLARITHROMYCIN Side Effects? Age & Gender Data

Is CLARITHROMYCIN Getting Safer? Reports by Year

What Is CLARITHROMYCIN Used For?

CLARITHROMYCIN vs Alternatives: Which Is Safer?

Other Drugs in Same Class: Cytochrome P450 3A Inhibitors [MoA]

Official FDA Label for CLARITHROMYCIN

Drug Description

FDA Approved Uses (Indications)

Acute Maxillary

Uncomplicated

Acute Otitis

1.4 Pharyngitis/Tonsillitis Clarithromycin tablets, USP are indicated for the treatment of mild to moderate infections caused by susceptible isolates due to Streptococcus pyogenes as an alternative in individuals who cannot use first line therapy.

1.5 Uncomplicated Skin and Skin Structure Infections Clarithromycin tablets, USP are indicated for the treatment of mild to moderate infections caused by susceptible isolates due to Staphylococcus aureus , or Streptococcus pyogenes .

1.9 Limitations of Use There is resistance to macrolides in certain bacterial infections caused by Streptococcus pneumoniae and Staphylococcus aureus . Susceptibility testing should be performed when clinically indicated.

1.4 Pharyngitis/Tonsillitis Clarithromycin tablets, USP are indicated for the treatment of mild to moderate infections caused by susceptible isolates due to Streptococcus pyogenes as an alternative in individuals who cannot use first line therapy.

1.5 Uncomplicated Skin and Skin Structure Infections Clarithromycin tablets, USP are indicated for the treatment of mild to moderate infections caused by susceptible isolates due to Staphylococcus aureus , or Streptococcus pyogenes .

1.9 Limitations of Use There is resistance to macrolides in certain bacterial infections caused by Streptococcus pneumoniae and Staphylococcus aureus . Susceptibility testing should be performed when clinically indicated.

Dosage & Administration

Pediatric

Mycobacterial

2.1 Important Administration Instructions Clarithromycin tablets may be given with or without food.

2.2 Adult Dosage The recommended dosages of clarithromycin for the treatment of mild to moderate infections in adults are listed in Table 1.

Table

Adult Dosage Guidelines

Adult Patients

Pediatric Patients

2.6 Dosage Adjustment in Patients with Renal Impairment See Table 2 for dosage adjustment in patients with moderate or severe renal impairment with or without concomitant atazanavir or ritonavir-containing regimens <span class="opacity-50 text-xs">[see Drug Interactions (7) ]</span> .

Table

Clarithromycin Dosage

2.1 Important Administration Instructions Clarithromycin tablets may be given with or without food.

2.2 Adult Dosage The recommended dosages of clarithromycin for the treatment of mild to moderate infections in adults are listed in Table 1.

Table

Adult Dosage Guidelines

Adult Patients

Pediatric Patients

2.6 Dosage Adjustment in Patients with Renal Impairment See Table 2 for dosage adjustment in patients with moderate or severe renal impairment with or without concomitant atazanavir or ritonavir-containing regimens <span class="opacity-50 text-xs">[see Drug Interactions (7) ]</span> .

Table

Clarithromycin Dosage

Contraindications

4.1 Hypersensitivity Clarithromycin is contraindicated in patients with a known hypersensitivity to clarithromycin, erythromycin, or any of the macrolide antibacterial drugs <span class="opacity-50 text-xs">[see Warnings and Precautions (5.1) ]</span> .

4.3 Cholestatic Jaundice/Hepatic Dysfunction Clarithromycin is contraindicated in patients with a history of cholestatic jaundice or hepatic dysfunction associated with prior use of clarithromycin.

4.4 Colchicine Concomitant administration of clarithromycin and colchicine is contraindicated in patients with renal or hepatic impairment.

4.6 Ergot Alkaloids Concomitant administration of clarithromycin and ergotamine or dihydroergotamine is contraindicated <span class="opacity-50 text-xs">[see Drug Interactions (7) ]</span> .

4.7 Lurasidone Concomitant administration of clarithromycin and lurasidone is contraindicated since it may result in an increase in lurasidone exposure and the potential for serious adverse reactions <span class="opacity-50 text-xs">[see Drug Interactions (7) ]</span> .

4.8 Contraindications for Co-administered Drugs For information about contraindications of other drugs indicated in combination with clarithromycin, refer to their full prescribing information (contraindications section).

4.1 Hypersensitivity Clarithromycin is contraindicated in patients with a known hypersensitivity to clarithromycin, erythromycin, or any of the macrolide antibacterial drugs <span class="opacity-50 text-xs">[see Warnings and Precautions (5.1) ]</span> .

4.3 Cholestatic Jaundice/Hepatic Dysfunction Clarithromycin is contraindicated in patients with a history of cholestatic jaundice or hepatic dysfunction associated with prior use of clarithromycin.

4.4 Colchicine Concomitant administration of clarithromycin and colchicine is contraindicated in patients with renal or hepatic impairment.

4.6 Ergot Alkaloids Concomitant administration of clarithromycin and ergotamine or dihydroergotamine is contraindicated <span class="opacity-50 text-xs">[see Drug Interactions (7) ]</span> .

4.7 Lurasidone Concomitant administration of clarithromycin and lurasidone is contraindicated since it may result in an increase in lurasidone exposure and the potential for serious adverse reactions <span class="opacity-50 text-xs">[see Drug Interactions (7) ]</span> .

4.8 Contraindications for Co-administered Drugs For information about contraindications of other drugs indicated in combination with clarithromycin, refer to their full prescribing information (contraindications section).

Known Adverse Reactions

Serious Adverse Reactions

Table

Incidence

Table

Approximately

Table

Selected

Trial

Abdominal Pain

Table

Adverse

Less Frequent Adverse Reactions Observed

Immune

Nervous

Table

Incidence

Table

Approximately

Table

Selected

Trial

Abdominal Pain

Table

Adverse

Less Frequent Adverse Reactions Observed