RIFAPENTINE Drug Interactions: What You Need to Know

INTERACTIONS Protease Inhibitors and Reverse Transcriptase Inhibitors. ( 5.2 , 7.1 )

Hormonal

Contraceptives: Use an effective non-hormonal method of contraception or add a barrier method of contraception during treatment with PRIFTIN. ( 7.3 ) May increase metabolism and decrease the activity of drugs metabolized by cytochrome P450 3A4 and 2C8/9. Dosage adjustments may be necessary if given concomitantly. ( 7.4 )

7.1 Protease Inhibitors and Reverse Transcriptase Inhibitors Rifapentine is an inducer of CYP450 enzymes. Concomitant use of PRIFTIN with other drugs metabolized by these enzymes, such as protease inhibitors and certain reverse transcriptase inhibitors, may cause a significant decrease in plasma concentrations and loss of therapeutic effect of the protease inhibitor or reverse transcriptase inhibitor <span class="opacity-50 text-xs">[see Warnings and Precautions (5.6) and Clinical Pharmacology (12.3) ]</span> .

7.2 Fixed-Dose Combination of Efavirenz, Emtricitabine, and Tenofovir Once-weekly coadministration of 900 mg PRIFTIN with the antiretroviral fixed-dose combination of efavirenz 600 mg, emtricitabine 200 mg and tenofovir disoproxil fumarate 300 mg in HIV-infected patients did not result in any substantial change in steady state exposures of efavirenz, emtricitabine, and tenofovir. No clinically significant change in CD4 cell counts or viral loads were noted <span class="opacity-50 text-xs">[see Clinical Pharmacology (12.3) ]</span> .

7.3 Hormonal Contraceptives PRIFTIN may reduce the effectiveness of hormonal contraceptives. Patients using hormonal contraception should be advised to use an alternative non-hormonal contraceptive method or add a barrier method of contraception during treatment with PRIFTIN <span class="opacity-50 text-xs">[see Use in Specific Populations (8.3) and Clinical Pharmacology (12.3) ]</span> .

7.4 Cytochrome P450 3A4 and 2C8/9 Rifapentine is an inducer of cytochromes P450 3A4 and P450 2C8/9. Therefore, PRIFTIN may increase the metabolism of other coadministered drugs that are metabolized by these enzymes. Induction of enzyme activities by PRIFTIN occurred within 4 days after the first dose. Enzyme activities returned to baseline levels 14 days after discontinuing PRIFTIN. Rifampin has been reported to accelerate the metabolism and may reduce the activity of the following drugs; hence, PRIFTIN may also increase the metabolism and decrease the activity of these drugs. Dosage adjustments of the drugs in Table 4 or of other drugs metabolized by cytochrome P450 3A4 or P450 2C8/9 may be necessary if they are given concurrently with PRIFTIN.

Table

4: Drug Interactions with PRIFTIN: Dosage Adjustment May be Necessary Drug Class Examples of Drugs Within Class Antiarrhythmics Disopyramide, mexiletine, quinidine, tocainide Antibiotics Chloramphenicol, clarithromycin, dapsone, doxycycline; Fluoroquinolones (such as ciprofloxacin)

Oral Anticoagulants Warfarin Anticonvulsants Phenytoin

Antimalarials Quinine Azole Antifungals Fluconazole, itraconazole, ketoconazole Antipsychotics Haloperidol Barbiturates Phenobarbital Benzodiazepines Diazepam Beta-Blockers Propranolol Calcium Channel Blockers Diltiazem, nifedipine, verapamil Cardiac Glycoside Preparations Digoxin Corticosteroids Prednisone Fibrates Clofibrate Oral Hypoglycemics Sulfonylureas (e.g., glyburide, glipizide)

Hormonal Contraceptives/Progestins

Ethinyl estradiol, levonorgestrel Immunosuppressants Cyclosporine, tacrolimus Methylxanthines Theophylline Narcotic analgesics Methadone Phosphodiesterase-5 (PDE-5)

Inhibitors Sildenafil

Thyroid preparations Levothyroxine Tricyclic antidepressants Amitriptyline, nortriptyline

7.5 Other Interactions The conversion of PRIFTIN to 25-desacetyl rifapentine is mediated by an esterase enzyme. There is minimal potential for PRIFTIN metabolism to be inhibited or induced by another drug, based upon the characteristics of the esterase enzymes. Since PRIFTIN is highly bound to albumin, drug displacement interactions may also occur <span class="opacity-50 text-xs">[see Clinical Pharmacology (12.3) ]</span> .

7.6 Interactions with Laboratory Tests Therapeutic concentrations of rifampin have been shown to inhibit standard microbiological assays for serum folate and Vitamin B 12 . Similar drug-laboratory interactions should be considered for PRIFTIN; thus, alternative assay methods should be considered.

Known hypersensitivity to any rifamycin. ( 4.1 )

4.1 Hypersensitivity PRIFTIN is contraindicated in patients with a history of hypersensitivity to rifamycins.

AND PRECAUTIONS Hepatotoxicity: Monitor for symptoms of liver injury and discontinue PRIFTIN if signs or symptoms or liver injury occur. ( 5.1 ) Hypersensitivity: Discontinue PRIFTIN if signs or symptoms of hypersensitivity reaction occur. ( 5.2 ) Severe cutaneous adverse reactions: Discontinue PRIFTIN at the first appearance of skin rash, mucosal lesions, or any other sign of hypersensitivity. ( 5.3 ) Relapse in the treatment of active pulmonary tuberculosis: Do not use as a once-weekly continuation phase regimen with isoniazid in HIV-infected patients. Monitor for signs or symptoms of relapse in patients with cavitary lesions or bilateral disease. ( 5.4 , 14.1 )

Paradoxical Drug

Reactions: If worsening of symptoms or signs occur during antimycobacterial treatment, consider paradoxical drug reaction in the differential diagnosis, and monitor or treat accordingly. ( 5.5 )

Drug

Interactions: May interact with drugs metabolized by CYP450. ( 5.6 , 7.1 , 7.4 ) Discoloration of body fluids: May permanently stain contact lenses or dentures red-orange. ( 5.7 ) Clostridioides difficile –associated diarrhea: Evaluate if diarrhea occurs. ( 5.8 ) Porphyria: Avoid use in patients with porphyria. ( 5.9 )

5.1 Hepatotoxicity Elevations of liver transaminases may occur in patients receiving PRIFTIN <span class="opacity-50 text-xs">[see Adverse Reactions (6.1) ]</span> . Patients on PRIFTIN should be monitored for symptoms of liver injury. Patients with abnormal liver tests and/or liver disease or patients initiating treatment for active pulmonary tuberculosis should only be given PRIFTIN in cases of necessity and under strict medical supervision. In such patients, obtain serum transaminase levels prior to therapy and every 2 to 4 weeks while on therapy. Discontinue PRIFTIN if evidence of liver injury occurs.

5.2 Hypersensitivity and Related Reactions Hypersensitivity reactions may occur in patients receiving PRIFTIN. Signs and symptoms of these reactions may include hypotension, urticaria, angioedema, acute bronchospasm, conjunctivitis, thrombocytopenia, neutropenia or flu-like syndrome (weakness, fatigue, muscle pain, nausea, vomiting, headache, fever, chills, aches, rash, itching, sweats, dizziness, shortness of breath, chest pain, cough, syncope, palpitations). There have been reports of anaphylaxis <span class="opacity-50 text-xs">[see Patient Counseling Information (17) ]</span> . Monitor patients receiving PRIFTIN therapy for signs and/or symptoms of hypersensitivity reactions. If these symptoms occur, administer supportive measures and discontinue PRIFTIN.

5.3 Severe Cutaneous Adverse Reactions Severe cutaneous adverse reactions (SCARs) such as Stevens-Johnson syndrome (SJS) and drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome have been reported in association with the use of rifapentine (PRIFTIN) treatment regimens in patients with active and latent tuberculosis. Discontinue PRIFTIN at the first appearance of skin rash, mucosal lesions, or any other sign of hypersensitivity <span class="opacity-50 text-xs">[see Patient Counseling Information (17) ]</span> .

5.4 Relapse in the Treatment of Active Pulmonary Tuberculosis PRIFTIN has not been evaluated as part of the initial phase treatment regimen in HIV-infected patients with active pulmonary TB. Do not use PRIFTIN as a once-weekly continuation phase regimen in HIV-infected patients with active pulmonary tuberculosis because of a higher rate of failure and/or relapse with rifampin-resistant organisms <span class="opacity-50 text-xs">[see Clinical Studies (14.1) ]</span> . Higher relapse rates may occur in patients with cavitary pulmonary lesions and/or positive sputum cultures after the initial phase of active tuberculosis treatment and in patients with evidence of bilateral pulmonary disease. Monitor for signs and symptoms of TB relapse in these patients <span class="opacity-50 text-xs">[see Clinical Studies (14.1) ]</span> . Poor adherence to therapy is associated with high relapse rate. Emphasize the importance of compliance with therapy <span class="opacity-50 text-xs">[see Patient Counseling Information (17) ]</span> .

5.5 Paradoxical Drug Reactions Paradoxical drug reactions are characterized by the recurrence or appearance of new symptoms or physical and radiological signs in a patient who had previously shown improvement with appropriate antimycobacterial treatment, in the absence of disease relapse, poor treatment compliance, drug resistance, side effects of treatment, or secondary infection/diagnosis. Paradoxical drug reactions have been reported with antimycobacterial therapy, including PRIFTIN, within the first few weeks or months of initiation of tuberculosis therapy <span class="opacity-50 text-xs">[see Adverse Reactions (6.2) ]</span> . Paradoxical drug reactions are often transient and should not be misinterpreted as failure to respond to treatment. If worsening of symptoms or signs occurs during antimycobacterial treatment, consider paradoxical drug reaction in the differential diagnosis, and monitor or treat accordingly. Advise patients to seek medical advice immediately if their symptoms of tuberculosis worsen or reappear.

5.6 Drug Interactions Rifapentine is an inducer of CYP450 enzymes. Concomitant use of rifapentine with other drugs metabolized by these enzymes, such as protease inhibitors, certain reverse transcriptase inhibitors, and hormonal contraception may cause a significant decrease in plasma concentrations and loss of therapeutic effect <span class="opacity-50 text-xs">[see Drug Interactions (7.1 , 7.2 , 7.3 , 7.4) and Clinical Pharmacology (12.3) ]</span> .

5.7 Discoloration of Body Fluids PRIFTIN may produce a red-orange discoloration of body tissues and/or fluids (e.g., skin, teeth, tongue, urine, feces, saliva, sputum, tears, sweat, and cerebrospinal fluid). Contact lenses or dentures may become permanently stained.

5.8 Clostridioides Difficile –Associated Diarrhea Clostridioides difficile –associated diarrhea (CDAD) has been reported with the use of nearly all systemic antibacterial agents, including PRIFTIN, with severity ranging from mild diarrhea to fatal colitis. Treatment with antibacterial agents can alter the normal flora of the colon and may permit 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 because CDAD has been reported to occur over two months after the administration of antibacterial agents. If CDAD is suspected or confirmed, discontinue antibacterial use not directed against C. difficile if possible. Institute appropriate measures such as fluid and electrolyte management, protein supplementation, antibacterial treatment of C. difficile , and surgical evaluation as clinically indicated.

5.9 Porphyria Porphyria has been reported in patients receiving rifampin, attributed to induction of delta amino levulinic acid synthetase. Because PRIFTIN may have similar enzyme induction properties, avoid the use of PRIFTIN in patients with porphyria.