DEXTROMETHORPHAN HYDROBROMIDE: 2,452 Adverse Event Reports & Safety Profile

NUEDEXTA is an oral formulation of dextromethorphan hydrobromide USP and quinidine sulfate USP in a fixed dose combination. Dextromethorphan hydrobromide is the pharmacologically active ingredient of NUEDEXTA that acts on the central nervous system (CNS). The chemical name is dextromethorphan hydrobromide: morphinan, 3-methoxy-17-methyl-, (9α, 13α, 14α), hydrobromide monohydrate. Dextromethorphan hydrobromide has the empirical formula C 18 H 25 NO•HBr•H 2 O with a molecular weight of 370.33. The structural formula is: Quinidine sulfate is a specific inhibitor of CYP2D6-dependent oxidative metabolism used in NUEDEXTA to increase the systemic bioavailability of dextromethorphan. The chemical name is quinidine sulfate: cinchonan-9-o1, 6'-methoxy-, (9S) sulfate (2:1), (salt), dihydrate. Quinidine sulfate dihydrate has the empirical formula of (C 20 H 24 N 2 O 2 ) 2

• H 2 SO 4
• 2H 2 O with a molecular weight of 782.96. The structural formula is: The combination product, NUEDEXTA, is a white to off-white powder. NUEDEXTA is available for oral use as NUEDEXTA which contains 20 mg dextromethorphan hydrobromide and 10 mg quinidine sulfate. The active ingredients are dextromethorphan hydrobromide monohydrate USP and quinidine sulfate dihydrate USP. Inactive ingredients in the capsule are croscarmellose sodium NF, microcrystalline cellulose NF, colloidal silicon dioxide NF, lactose monohydrate NF, and magnesium stearate NF. The structural formula for Dextromethorphan hydrobromide is the pharmacologically active ingredient of NUEDEXTA that acts on the central nervous system (CNS). The chemical name is dextromethorphan hydrobromide: morphinan, 3-methoxy-17-methyl-, (9α, 13α, 14α), hydrobromide monohydrate. Dextromethorphan hydrobromide has the empirical formula C18H25NO•HBr•H2O with a molecular weight of 370.33. The structural formula for Quinidine sulfate is a specific inhibitor of CYP2D6-dependent oxidative metabolism used in NUEDEXTA to increase the systemic bioavailability of dextromethorphan. The chemical name is quinidine sulfate: cinchonan-9-o1, 6'-methoxy-, (9S) sulfate (2:1), (salt), dihydrate. Quinidine sulfate dihydrate has the empirical formula of (C20H24N2O2)2•H2SO4•2H2O with a molecular weight of 782.96.

Uses

• helps loosen phlegm (mucus) and thin bronchial secretions to rid the bronchial passageways of bothersome mucus and make coughs more productive
• temporarily relieves:
• cough due to minor throat and bronchial irritation as may occur with the common cold or inhaled irritants
• the intensity of coughing
• the impulse to cough to help you get to sleep Warnings Do not use
• for children under 12 years of age
• if you are now taking a prescription monoamine oxidase inhibitor (MAOI) (certain drugs for depression, psychiatric or emotional conditions, or Parkinson’s disease), or for 2 weeks after stopping the MAOI drug. If you do not know if your prescription drug contains an MAOI, ask a doctor or pharmacist before taking this product. Ask a doctor before use if you have
• persistent or chronic cough such as occurs with smoking, asthma, chronic bronchitis, or emphysema
• cough accompanied by too much phlegm (mucus) When using this product
• do not use more than directed Stop use and ask a doctor if
• cough lasts more than 7 days, comes back, or occurs with fever, rash, or persistent headache. These could be signs of a serious illness. If pregnant or breast-feeding, ask a health professional before use. Keep out of reach of children. In case of overdose, get medical help or contact a Poison Control Center right away. (1-800-222-1222)

DOSAGE AND ADMINISTRATION It is important that Promethazine Hydrochloride and Dextromethorphan Hydrobromide Oral Solution is measured with an accurate measuring device (see PRECAUTIONS – Information for Patients ). A household teaspoon is not an accurate measuring device and could lead to overdosage, especially when half a teaspoon is to be measured. It is strongly recommended that an accurate measuring device be used. A pharmacist can provide an appropriate device and can provide instructions for measuring the correct dose.

Promethazine

Hydrochloride and Dextromethorphan Hydrobromide Oral Solution is CONTRAINDICATED for children under 2 years of age (see WARNINGS – Boxed Warning and Use in Pediatric Patients ). The average effective dose for adults is 5 mL (one teaspoon) every 4 to 6 hours, not to exceed 30.0 mL in 24 hours. For children 6 years to under 12 years of age, the dose is 2.5 to 5.0 mL (one-half to one teaspoon) every 4 to 6 hours, not to exceed 20.0 mL in 24 hours. For children 2 years to under 6 years of age, the dose is 1.25 to 2.5 mL (one-quarter to one-half teaspoon) every 4 to 6 hours, not to exceed 10.0 mL in 24 hours.

Concomitant use with quinidine, quinine, or mefloquine. ( 4.1 ) Patients with a history of quinidine, quinine or mefloquine-induced thrombocytopenia, hepatitis, or other hypersensitivity reactions. ( 4.2 ) Patients with known hypersensitivity to dextromethorphan. ( 4.2 ) Use with an MAOI or within 14 days of stopping an MAOI.

Allow

14 days after stopping dextromethorphan hydrobromide and quinidine sulfate before starting an MAOI. ( 4.3 ) Prolonged QT interval, congenital long QT syndrome, history suggestive of torsades de pointes, or heart failure. ( 4.4 ) Complete atrioventricular (AV) block without implanted pacemaker, or patients at high risk of complete AV block. ( 4.4 ) Concomitant use with drugs that both prolong QT interval and are metabolized by CYP2D6 (e.g., thioridazine or pimozide). ( 4.4 )

4.1 Quinidine and Related Drugs Dextromethorphan hydrobromide and quinidine sulfate capsules contain quinidine and should not be used concomitantly with other drugs containing quinidine, quinine, or mefloquine.

4.2 Hypersensitivity Dextromethorphan hydrobromide and quinidine sulfate capsules are contraindicated in patients with a history of dextromethorphan hydrobromide and quinidine sulfate, quinine, mefloquine or quinidine-induced thrombocytopenia, hepatitis, bone marrow depression or lupus-like syndrome. Dextromethorphan hydrobromide and quinidine sulfate capsules are also contraindicated in patients with a known hypersensitivity to dextromethorphan (e.g. rash, hives) <span class="opacity-50 text-xs">[see Warnings and Precautions ( 5.1 )]</span> .

4.3 MAOIs Dextromethorphan hydrobromide and quinidine sulfate capsules are contraindicated in patients taking monoamine oxidase inhibitors (MAOIs) or in patients who have taken MAOIs within the preceding 14 days, due to the risk of serious and possibly fatal drug interactions, including serotonin syndrome. Allow at least 14 days after stopping dextromethorphan hydrobromide and quinidine sulfate capsules before starting an MAOI <span class="opacity-50 text-xs">[see Drug Interactions ( 7.1 )]</span> .

4.4 Cardiovascular Dextromethorphan hydrobromide and quinidine sulfate capsules are contraindicated in patients with a prolonged QT interval, congenital long QT syndrome or a history suggestive of torsades de pointes, and in patients with heart failure <span class="opacity-50 text-xs">[see Warnings and Precautions ( 5.3 )]</span> . Dextromethorphan hydrobromide and quinidine sulfate capsules are contraindicated in patients receiving drugs that both prolong QT interval and are metabolized by CYP2D6 (e.g., thioridazine and pimozide), as effects on QT interval may be increased <span class="opacity-50 text-xs">[see Drug Interactions ( 7.2 )]</span> . Dextromethorphan hydrobromide and quinidine sulfate capsules are contraindicated in patients with complete atrioventricular (AV) block without implanted pacemakers, or in patients who are at high risk of complete AV block.

REACTIONS A total of 946 patients participated in four Phase 3 controlled and uncontrolled PBA studies and received at least one dose of the combination product of dextromethorphan/quinidine in various strengths at the recommended or higher than the recommended dose. Of those patients, 393 patients were exposed for at least 180 days and 294 patients were exposed for at least one year. Median exposure was 168 days. Controlled trials enrolled only patients with either ALS or MS. Uncontrolled studies enrolled 136 patients with PBA secondary to a wide variety of underlying neurological conditions including stroke (45 patients) and traumatic brain injury (23 patients). Consequently, patients with other underlying neurologic diseases may experience other adverse reactions not described below. The most common adverse reactions (incidence of ≥ 3% and two-fold greater than placebo) in patients taking dextromethorphan hydrobromide and quinidine sulfate are diarrhea, dizziness, cough, vomiting, asthenia, peripheral edema, urinary tract infection, influenza, increased gamma-glutamyltransferase, and flatulence. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Hetero Labs Limited at 1-866-495-1995 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

6.1 Clinical Trials Experience A 12-week, placebo-controlled study evaluated dextromethorphan hydrobromide and quinidine sulfate (dextromethorphan 20 mg/quinidine 10 mg) (N=107) and a 30 mg dextromethorphan/10 mg quinidine combination (N=110) compared to placebo (N=109).

Approximately

60% of patients had ALS and 40% had MS. Patients were 25 to 80 years of age, with a mean age of approximately 51 years. Three (3) ALS patients in each drug treatment arm and 1 ALS patient in the placebo arm died during the 12-week placebo-control period. All deaths were consistent with the natural progression of ALS.

Adverse Reactions

Leading to Discontinuation The most commonly reported adverse reactions (incidence ≥ 2% and greater than placebo) that led to discontinuation with the 20 mg dextromethorphan/10 mg quinidine twice daily dose were muscle spasticity (3%), respiratory failure (1%), abdominal pain (2%), asthenia (2%), dizziness (2%), fall (1%), and muscle spasms (2%).

Most Common Adverse Reactions

Adverse drug reactions that occurred in ≥ 3% of patients receiving the 20 mg dextromethorphan/10 mg quinidine twice daily dose, and at an incidence of ≥ 2 times placebo in short-term clinical trials in ALS and MS are provided in Table 1. Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to the rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice.

Table

1: Adverse Drug Reactions with an Incidence of ≥3% of Patients and ≥ 2x Placebo in Dextromethorphan Hydrobromide and Quinidine Sulfate-treated Patients by System-Organ Class and Preferred Term Dextromethorphan Hydrobromide and Quinidine Sulfate N=107 % Placebo N=109 % Diarrhea 13 6 Dizziness 10 5 Cough 5 2 Vomiting 5 1 Asthenia 5 2 Peripheral edema 5 1 Urinary tract infection 4 1 Influenza 4 1 Increased gamma- glutamyltransferase 3 0 Flatulence 3 1

6.2 Long-Term Exposure with Dextromethorphan Hydrobromide and Quinidine Sulfate The experience in open-label clinical trials is consistent with the safety profile observed in the placebo-controlled clinical trials.

6.3 Safety Experience of Individual Components The following adverse reactions have been reported with the use of the individual components of dextromethorphan hydrobromide and quinidine sulfate, dextromethorphan and quinidine, from post-marketing experience. Because these reactions are reported voluntarily from a population of unknown size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

Dextromethorphan

Drowsiness, dizziness, nervousness or restlessness, nausea, vomiting, and stomach pain.

Quinidine

Cinchonism is most often a sign of chronic quinidine toxicity, but it may appear in sensitive patients after a single moderate dose of several hundred milligrams. Cinchonism is characterized by nausea, vomiting, diarrhea, headache tinnitus, hearing loss, vertigo, blurred vision, diplopia, photophobia, confusion, and delirium. Convulsions, apprehension, and ataxia have been reported with quinidine therapy, but it is not clear that these were not simply the results of hypotension and consequent cerebral hypoperfusion in patients being treated for cardiovascular indications. Acute psychotic reactions have been reported to follow the first dose of quinidine, but these reactions appear to be extremely rare. Other adverse reactions occasionally reported with quinidine therapy include depression, mydriasis, disturbed color perception, night blindness, scotomata, optic neuritis, visual field loss, photosensitivity, keratopathy, and abnormalities of skin pigmentation.

WARNINGS WARNING PROMETHAZINE HYDROCHLORIDE SHOULD NOT BE USED IN PEDIATRIC PATIENTS LESS THAN 2 YEARS OF AGE BECAUSE OF THE POTENTIAL FOR FATAL RESPIRATORY DEPRESSION. POSTMARKETING CASES OF RESPIRATORY DEPRESSION, INCLUDING FATALITIES, HAVE BEEN REPORTED WITH USE OF PROMETHAZINE HYDROCHLORIDE IN PEDIATRIC PATIENTS LESS THAN 2 YEARS OF AGE. A WIDE RANGE OF WEIGHT-BASED DOSES OF PROMETHAZINE HYDROCHLORIDE HAVE RESULTED IN RESPIRATORY DEPRESSION IN THESE PATIENTS. CAUTION SHOULD BE EXERCISED WHEN ADMINISTERING PROMETHAZINE HYDROCHLORIDE TO PEDIATRIC PATIENTS 2 YEARS OF AGE AND OLDER. IT IS RECOMMENDED THAT THE LOWEST EFFECTIVE DOSE OF PROMETHAZINE HYDROCHLORIDE BE USED IN PEDIATRIC PATIENTS 2 YEARS OF AGE AND OLDER AND CONCOMITANT ADMINISTRATION OF OTHER DRUGS WITH RESPIRATORY DEPRESSANT EFFECTS BE AVOIDED.

Dextromethorphan

Administration of dextromethorphan may be accompanied by histamine release and should be used with caution in atopic children. Promethazine CNS Depression Promethazine may impair the mental and/or physical abilities required for the performance of potentially hazardous tasks, such as driving a vehicle or operating machinery. The impairment may be amplified by concomitant use of other central-nervous-system depressants such as alcohol, sedatives/hypnotics (including barbiturates), narcotics, narcotic analgesics, general anesthetics, tricyclic antidepressants, and tranquilizers; therefore such agents should either be eliminated or given in reduced dosage in the presence of promethazine HCl (see PRECAUTIONS-Information for Patients and Drug Interactions ).

Respiratory Depression

Promethazine may lead to potentially fatal respiratory depression. Use of Promethazine in patients with compromised respiratory function (e.g., COPD, sleep apnea) should be avoided.

Lower Seizure Threshold

Promethazine may lower seizure threshold. It should be used with caution in persons with seizure disorders or in persons who are using concomitant medications, such as narcotics or local anesthetics, which may also affect seizure threshold. Bone-Marrow Depression Promethazine should be used with caution in patients with bone-marrow depression. Leukopenia and agranulocytosis have been reported, usually when promethazine HCl has been used in association with other known marrow-toxic agents.

Neuroleptic Malignant

Syndrome A potentially fatal symptom complex sometimes referred to as Neuroleptic Malignant Syndrome (NMS) has been reported in association with promethazine HCl alone or in combination with antipsychotic drugs. Clinical manifestations of NMS are hyperpyrexia, muscle rigidity, altered mental status and evidence of autonomic instability (irregular pulse or blood pressure, tachycardia, diaphoresis and cardiac dysrhythmias). The diagnostic evaluation of patients with this syndrome is complicated. In arriving at a diagnosis, it is important to identify cases where the clinical presentation includes both serious medical illness (e.g. pneumonia, systemic infection, etc.) and untreated or inadequately treated extrapyramidal signs and symptoms (EPS). Other important considerations in the differential diagnosis include central anticholinergic toxicity, heat stroke, drug fever and primary central nervous system (CNS) pathology. The management of NMS should include 1) immediate discontinuation of promethazine HCl, antipsychotic drugs, if any, and other drugs not essential to concurrent therapy, 2) intensive symptomatic treatment and medical monitoring, and 3) treatment of any concomitant serious medical problems for which specific treatments are available. There is no general agreement about specific pharmacological treatment regimens for uncomplicated NMS. Since recurrences of NMS have been reported with phenothiazines, the reintroduction of promethazine HCl should be carefully considered.

Use In Pediatric

Patients PROMETHAZINE PRODUCTS ARE CONTRAINDICATED FOR USE IN PEDIATRIC PATIENTS LESS THAN TWO YEARS OF AGE. CAUTION SHOULD BE EXERCISED WHEN ADMINISTERING PROMETHAZINE PRODUCTS TO PEDIATRIC PATIENTS 2 YEARS OF AGE AND OLDER BECAUSE OF THE POTENTIAL FOR FATAL RESPIRATORY DEPRESSION. RESPIRATORY DEPRESSION AND APNEA, SOMETIMES ASSOCIATED WITH DEATH, ARE STRONGLY ASSOCIATED WITH PROMETHAZINE PRODUCTS AND ARE NOT DIRECTLY RELATED TO INDIVIDUALIZED WEIGHT-BASED DOSING, WHICH MIGHT OTHERWISE PERMIT SAFE ADMINISTRATION. CONCOMITANT ADMINISTRATION OF PROMETHAZINE PRODUCTS WITH OTHER RESPIRATORY DEPRESSANTS HAS AN ASSOCIATION WITH RESPIRATORY DEPRESSION, AND SOMETIMES DEATH, IN PEDIATRIC PATIENTS. ANTIEMETICS ARE NOT RECOMMENDED FOR TREATMENT OF UNCOMPLICATED VOMITING IN PEDIATRIC PATIENTS, AND THEIR USE SHOULD BE LIMITED TO PROLONGED VOMITING OF KNOWN ETIOLOGY. THE EXTRAPYRAMIDAL SYMPTOMS WHICH CAN OCCUR SECONDARY TO PROMETHAZINE HYDROCHLORIDE ADMINISTRATION MAY BE CONFUSED WITH THE CNS SIGNS OF UNDIAGNOSED PRIMARY DISEASE, e.g., ENCEPHALOPATHY OR REYE'S SYNDROME. THE USE OF PROMETHAZINE PRODUCTS SHOULD BE AVOIDED IN PEDIATRIC PATIENTS WHOSE SIGNS AND SYMPTOMS MAY SUGGEST REYE'S SYNDROME OR OTHER HEPATIC DISEASES. Excessively large dosages of antihistamines, including promethazine hydrochloride, in pediatric patients may cause sudden death (see OVERDOSAGE ). Hallucinations and convulsions have occurred with therapeutic doses and overdoses of promethazine hydrochloride in pediatric patients. In pediatric patients who are acutely ill associated with dehydration, there is an increased susceptibility to dystonias with the use of promethazine HCl.

Other Consideration

Administration of promethazine has been associated with reported cholestatic jaundice.

WARNING PROMETHAZINE HYDROCHLORIDE SHOULD NOT BE USED IN PEDIATRIC PATIENTS LESS THAN 2 YEARS OF AGE BECAUSE OF THE POTENTIAL FOR FATAL RESPIRATORY DEPRESSION. POSTMARKETING CASES OF RESPIRATORY DEPRESSION, INCLUDING FATALITIES, HAVE BEEN REPORTED WITH USE OF PROMETHAZINE HYDROCHLORIDE IN PEDIATRIC PATIENTS LESS THAN 2 YEARS OF AGE. A WIDE RANGE OF WEIGHT-BASED DOSES OF PROMETHAZINE HYDROCHLORIDE HAVE RESULTED IN RESPIRATORY DEPRESSION IN THESE PATIENTS. CAUTION SHOULD BE EXERCISED WHEN ADMINISTERING PROMETHAZINE HYDROCHLORIDE TO PEDIATRIC PATIENTS 2 YEARS OF AGE AND OLDER. IT IS RECOMMENDED THAT THE LOWEST EFFECTIVE DOSE OF PROMETHAZINE HYDROCHLORIDE BE USED IN PEDIATRIC PATIENTS 2 YEARS OF AGE AND OLDER AND CONCOMITANT ADMINISTRATION OF OTHER DRUGS WITH RESPIRATORY DEPRESSANT EFFECTS BE AVOIDED.

Dextromethorphan

Administration of dextromethorphan may be accompanied by histamine release and should be used with caution in atopic children.

Promethazine CNS Depression Promethazine may impair the mental and/or physical abilities required for the performance of potentially hazardous tasks, such as driving a vehicle or operating machinery. The impairment may be amplified by concomitant use of other central-nervous-system depressants such as alcohol, sedatives/hypnotics (including barbiturates), narcotics, narcotic analgesics, general anesthetics, tricyclic antidepressants, and tranquilizers; therefore such agents should either be eliminated or given in reduced dosage in the presence of promethazine HCl (see PRECAUTIONS-Information for Patients and Drug Interactions ).

Respiratory Depression

Promethazine may lead to potentially fatal respiratory depression. Use of Promethazine in patients with compromised respiratory function (e.g., COPD, sleep apnea) should be avoided.

Lower Seizure Threshold

Promethazine may lower seizure threshold. It should be used with caution in persons with seizure disorders or in persons who are using concomitant medications, such as narcotics or local anesthetics, which may also affect seizure threshold. Bone-Marrow Depression Promethazine should be used with caution in patients with bone-marrow depression. Leukopenia and agranulocytosis have been reported, usually when promethazine HCl has been used in association with other known marrow-toxic agents.

Neuroleptic Malignant

Syndrome A potentially fatal symptom complex sometimes referred to as Neuroleptic Malignant Syndrome (NMS) has been reported in association with promethazine HCl alone or in combination with antipsychotic drugs. Clinical manifestations of NMS are hyperpyrexia, muscle rigidity, altered mental status and evidence of autonomic instability (irregular pulse or blood pressure, tachycardia, diaphoresis and cardiac dysrhythmias). The diagnostic evaluation of patients with this syndrome is complicated. In arriving at a diagnosis, it is important to identify cases where the clinical presentation includes both serious medical illness (e.g. pneumonia, systemic infection, etc.) and untreated or inadequately treated extrapyramidal signs and symptoms (EPS). Other important considerations in the differential diagnosis include central anticholinergic toxicity, heat stroke, drug fever and primary central nervous system (CNS) pathology. The management of NMS should include 1) immediate discontinuation of promethazine HCl, antipsychotic drugs, if any, and other drugs not essential to concurrent therapy, 2) intensive symptomatic treatment and medical monitoring, and 3) treatment of any concomitant serious medical problems for which specific treatments are available. There is no general agreement about specific pharmacological treatment regimens for uncomplicated NMS. Since recurrences of NMS have been reported with phenothiazines, the reintroduction of promethazine HCl should be carefully considered.

Cns

Depression Promethazine may impair the mental and/or physical abilities required for the performance of potentially hazardous tasks, such as driving a vehicle or operating machinery. The impairment may be amplified by concomitant use of other central-nervous-system depressants such as alcohol, sedatives/hypnotics (including barbiturates), narcotics, narcotic analgesics, general anesthetics, tricyclic antidepressants, and tranquilizers; therefore such agents should either be eliminated or given in reduced dosage in the presence of promethazine HCl (see PRECAUTIONS-Information for Patients and Drug Interactions ).

Respiratory Depression

Promethazine may lead to potentially fatal respiratory depression. Use of Promethazine in patients with compromised respiratory function (e.g., COPD, sleep apnea) should be avoided.

Lower Seizure Threshold

Promethazine may lower seizure threshold. It should be used with caution in persons with seizure disorders or in persons who are using concomitant medications, such as narcotics or local anesthetics, which may also affect seizure threshold.

Bone-Marrow Depression Promethazine should be used with caution in patients with bone-marrow depression. Leukopenia and agranulocytosis have been reported, usually when promethazine HCl has been used in association with other known marrow-toxic agents.

Neuroleptic Malignant

Syndrome A potentially fatal symptom complex sometimes referred to as Neuroleptic Malignant Syndrome (NMS) has been reported in association with promethazine HCl alone or in combination with antipsychotic drugs. Clinical manifestations of NMS are hyperpyrexia, muscle rigidity, altered mental status and evidence of autonomic instability (irregular pulse or blood pressure, tachycardia, diaphoresis and cardiac dysrhythmias). The diagnostic evaluation of patients with this syndrome is complicated. In arriving at a diagnosis, it is important to identify cases where the clinical presentation includes both serious medical illness (e.g. pneumonia, systemic infection, etc.) and untreated or inadequately treated extrapyramidal signs and symptoms (EPS). Other important considerations in the differential diagnosis include central anticholinergic toxicity, heat stroke, drug fever and primary central nervous system (CNS) pathology. The management of NMS should include 1) immediate discontinuation of promethazine HCl, antipsychotic drugs, if any, and other drugs not essential to concurrent therapy, 2) intensive symptomatic treatment and medical monitoring, and 3) treatment of any concomitant serious medical problems for which specific treatments are available. There is no general agreement about specific pharmacological treatment regimens for uncomplicated NMS. Since recurrences of NMS have been reported with phenothiazines, the reintroduction of promethazine HCl should be carefully considered.

Use In Pediatric

Patients PROMETHAZINE PRODUCTS ARE CONTRAINDICATED FOR USE IN PEDIATRIC PATIENTS LESS THAN TWO YEARS OF AGE. CAUTION SHOULD BE EXERCISED WHEN ADMINISTERING PROMETHAZINE PRODUCTS TO PEDIATRIC PATIENTS 2 YEARS OF AGE AND OLDER BECAUSE OF THE POTENTIAL FOR FATAL RESPIRATORY DEPRESSION. RESPIRATORY DEPRESSION AND APNEA, SOMETIMES ASSOCIATED WITH DEATH, ARE STRONGLY ASSOCIATED WITH PROMETHAZINE PRODUCTS AND ARE NOT DIRECTLY RELATED TO INDIVIDUALIZED WEIGHT-BASED DOSING, WHICH MIGHT OTHERWISE PERMIT SAFE ADMINISTRATION. CONCOMITANT ADMINISTRATION OF PROMETHAZINE PRODUCTS WITH OTHER RESPIRATORY DEPRESSANTS HAS AN ASSOCIATION WITH RESPIRATORY DEPRESSION, AND SOMETIMES DEATH, IN PEDIATRIC PATIENTS. ANTIEMETICS ARE NOT RECOMMENDED FOR TREATMENT OF UNCOMPLICATED VOMITING IN PEDIATRIC PATIENTS, AND THEIR USE SHOULD BE LIMITED TO PROLONGED VOMITING OF KNOWN ETIOLOGY. THE EXTRAPYRAMIDAL SYMPTOMS WHICH CAN OCCUR SECONDARY TO PROMETHAZINE HYDROCHLORIDE ADMINISTRATION MAY BE CONFUSED WITH THE CNS SIGNS OF UNDIAGNOSED PRIMARY DISEASE, e.g., ENCEPHALOPATHY OR REYE'S SYNDROME. THE USE OF PROMETHAZINE PRODUCTS SHOULD BE AVOIDED IN PEDIATRIC PATIENTS WHOSE SIGNS AND SYMPTOMS MAY SUGGEST REYE'S SYNDROME OR OTHER HEPATIC DISEASES. Excessively large dosages of antihistamines, including promethazine hydrochloride, in pediatric patients may cause sudden death (see OVERDOSAGE ). Hallucinations and convulsions have occurred with therapeutic doses and overdoses of promethazine hydrochloride in pediatric patients. In pediatric patients who are acutely ill associated with dehydration, there is an increased susceptibility to dystonias with the use of promethazine HCl.

Other Consideration

Administration of promethazine has been associated with reported cholestatic jaundice.

PRECAUTIONS General Drugs having anticholinergic properties should be used with caution in patients with narrow-angle glaucoma, prostatic hypertrophy, stenosing peptic ulcer, pyloroduodenal obstruction and bladder-neck obstruction.

Promethazine

Hydrochloride and Dextromethorphan Hydrobromide Oral Solution should be used cautiously in persons with cardiovascular disease or with impairment of liver function. Dextromethorphan should be used with caution in sedated patients, in the debilitated, and in patients confined to the supine position. Information for Patients Patients should be advised to measure Promethazine Hydrochloride and Dextromethorphan Hydrobromide Oral Solution with an accurate measuring device. A household teaspoon is not an accurate measuring device and could lead to overdosage, especially when a half a teaspoon is measured. A pharmacist can recommend an appropriate measuring device and can provide instructions for measuring the correct dose.

Promethazine

Hydrochloride and Dextromethorphan Hydrobromide Oral Solution may cause marked drowsiness or impair the mental and/or physical abilities required for the performance of potentially hazardous tasks, such as driving a vehicle or operating machinery. Ambulatory patients should be told to avoid engaging in such activities until it is known that they do not become drowsy or dizzy from promethazine and dextromethorphan therapy. Pediatric patients should be supervised to avoid potential harm in bike riding or in other hazardous activities. The concomitant use of alcohol or other central-nervous-system depressants, such as sedatives/hypnotics (including barbiturates), narcotics, narcotic analgesics, general anesthetics, tricyclic antidepressants, and tranquilizers, may enhance impairment (see WARNINGS – CNS Depression and PRECAUTIONS – Drug Interactions ). Patients should be advised to report any involuntary muscle movements. Avoid prolonged exposure to the sun.

Drug Interactions Monoamine

Oxidase (MAO) Inhibitors – Hyperpyrexia, hypotension, and death have been reported coincident with the co-administration of monoamine oxidase (MAO) inhibitors and products containing dextromethorphan. Drug interactions, including an increased incidence of extrapyramidal effects, have been reported when some MAO inhibitors and phenothiazines are used concomitantly. Thus, concomitant administration of Promethazine Hydrochloride and Dextromethorphan Hydrobromide Oral Solution and MAO inhibitors should be avoided (see CONTRAINDICATIONS ).

Cns

Depressants – Promethazine may increase, prolong, or intensify the sedative action of other central-nervous-system depressants, such as alcohol, sedatives/hypnotics (including barbiturates), narcotics, narcotic analgesics, general anesthetics, tricyclic antidepressants, and tranquilizers; therefore, such agents should be avoided or administered in reduced dosage to patients receiving promethazine. When given concomitantly with Promethazine Hydrochloride and Dextromethorphan Hydrobromide Oral Solution, the dose of barbiturates should be reduced by at least one-half, and the dose of narcotics should be reduced by one-quarter to one-half. Dosage must be individualized. Excessive amounts of promethazine relative to a narcotic may lead to restlessness and motor hyperactivity in the patient with pain; these symptoms usually disappear with adequate control of the pain. Epinephrine – Because of the potential for promethazine to reverse epinephrine’s vasopressor effect, epinephrine should NOT be used to treat hypotension associated with Promethazine Hydrochloride and Dextromethorphan Hydrobromide Oral Solution overdose. Anticholinergics – Concomitant use of other agents with anticholinergic properties should be undertaken with caution.

Drug/Laboratory

Test Interactions The following laboratory tests may be affected in patients who are receiving therapy with promethazine: Pregnancy Tests Diagnostic pregnancy tests based on immunological reactions between HCG and anti-HCG may result in false-negative or false-positive interpretations.

Glucose Tolerance

Test An increase in blood glucose has been reported in patients receiving promethazine. Carcinogenesis, Mutagenesis, Impairment of Fertility Long-term animal studies have not been performed to assess the carcinogenic potential of promethazine or of dextromethorphan. There are no animal or human data concerning carcinogenicity, mutagenicity, or impairment of fertility with these drugs. Promethazine was nonmutagenic in the Salmonella test system of Ames.

Pregnancy Teratogenic Effects

Teratogenic effects have not been demonstrated in rat-feeding studies at doses of 6.25 and 12.5 mg/kg of promethazine. These doses are 8.3 and 16.7 times the maximum recommended total daily dose for a 50-kg subject. Daily doses of 25 mg/kg intraperitoneally have been found to produce fetal mortality in rats. Specific studies to test the action of promethazine on parturition, lactation, and development of the animal neonate were not done, but a general preliminary study in rats indicated no effect on these parameters. Although antihistamines, including promethazine, have been found to produce fetal mortality in rodents, the pharmacological effects of histamine in the rodent do not parallel those in man. There are no adequate and well-controlled studies of promethazine in pregnant women. Animal reproduction studies have not been conducted with the drug combination – promethazine and dextromethorphan. It is not known whether this drug combination can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity.

Promethazine

Hydrochloride and Dextromethorphan Hydrobromide Oral Solution should be given to a pregnant woman only if clearly needed.

Promethazine

Hydrochloride and Dextromethorphan Hydrobromide Oral Solution should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Nonteratogenic Effects

Promethazine administered to a pregnant woman within two weeks of delivery may inhibit platelet aggregation in the newborn. Labor and Delivery Limited data suggest that use of promethazine during labor and delivery does not have an appreciable effect on the duration of labor or delivery and does not increase the risk of need for intervention in the newborn. The effect on later growth and development of the newborn is unknown. See also Nonteratogenic Effects.

Nursing

Mothers It is not known whether promethazine or dextromethorphan is excreted in human milk. Because many drugs are excreted in human milk and because of the potential for serious adverse reactions in nursing infants from Promethazine Hydrochloride and Dextromethorphan Hydrobromide Oral Solution, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.

Pediatric Use Promethazine

Hydrochloride and Dextromethorphan Hydrobromide Oral Solution is contraindicated for use in pediatric patients less than two years of age (see WARNINGS – Boxed Warning and Use in Pediatric Patients ) .

Promethazine

Hydrochloride and Dextromethorphan Hydrobromide Oral Solution should be used with caution in pediatric patients 2 years of age and older (see WARNINGS – Use in Pediatric Patients ).

Geriatric Use

Clinical studies of promethazine formulations did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal or cardiac function, and of concomitant disease or other drug therapy. Sedating drugs may cause confusion and over-sedation in the elderly; elderly patients generally should be started on low doses of Promethazine Hydrochloride and Dextromethorphan Hydrobromide Oral Solution and observed closely.

INTERACTIONS Desipramine: Exposure increases 8-fold. Reduce desipramine dose and adjust based on clinical response. ( 7.5 , 12.4 ) Paroxetine: Exposure increases 2-fold. Reduce paroxetine dose and adjust based on clinical response. ( 7.5 , 12.4 ) Digoxin: Increased digoxin substrate plasma concentration may occur. ( 7.6 )

7.1 MAOIs Do not use dextromethorphan hydrobromide and quinidine sulfate with monoamine oxidase inhibitors (MAOIs) or in patients who have taken MAOIs within the preceding 14 days <span class="opacity-50 text-xs">[see Contraindications ( 4.3 )]</span> .

7.2 Drugs that Prolong QT and are Metabolized by CYP2D6 Do not use with drugs that both prolong QT interval and are metabolized by CYP2D6 (e.g., thioridazine or pimozide) <span class="opacity-50 text-xs">[see Contraindications ( 4.4 )]</span> .

7.3 Drugs that Prolong QT and Concomitant CYP3A4 Inhibitors Recommend ECG in patients taking drugs with dextromethorphan hydrobromide and quinidine sulfate that prolong the QT interval and in patients taking concomitant moderate or strong CYP3A4 inhibitors <span class="opacity-50 text-xs">[see Warnings and Precautions ( 5.3 )]</span> .

7.4 SSRIs and Tricyclic Antidepressants Use of dextromethorphan hydrobromide and quinidine sulfate with SSRIs or tricyclic antidepressants increases the risk of ‘serotonin syndrome’ <span class="opacity-50 text-xs">[see Warnings and Precautions ( 5.6 )]</span> .

7.5 CYP2D6 Substrate The co-administration of dextromethorphan hydrobromide and quinidine sulfate with drugs that undergo extensive CYP2D6 metabolism may result in altered drug effects, due to accumulation of parent drug and/or failure of metabolite formation <span class="opacity-50 text-xs">[see Warnings and Precautions ( 5.4 )]</span>. Therapy with medications that are primarily metabolized by CYP2D6 and that have a relatively narrow therapeutic index should be initiated at a low dose if a patient is receiving dextromethorphan hydrobromide and quinidine sulfate concurrently. If dextromethorphan hydrobromide and quinidine sulfate is added to the treatment regimen of a patient already receiving a drug primarily metabolized by CYP2D6, the need for a dose modification of the original medication should be considered. The extent to which CYP2D6 interactions may pose clinical problems will depend on the pharmacokinetics of the substrate involved. In cases of prodrugs whose actions are mediated by the CYP2D6-produced metabolites (for example, codeine and hydrocodone, whose analgesic and antitussive effects appear to be mediated by morphine and hydromorphone, respectively), it may not be possible to achieve the desired clinical benefits in the presence of dextromethorphan hydrobromide and quinidine sulfate due to quinidine-mediated inhibition of CYP2D6. Consider use of alternative treatment with dextromethorphan hydrobromide and quinidine sulfate when clinically indicated. Drug interactions with desipramine and paroxetine have been studied in controlled clinical trials with a higher dose combination of dextromethorphan/quinidine (dextromethorphan 30 mg/quinidine 30 mg) than dextromethorphan hydrobromide and quinidine sulfate; study results are described below. No other drug interactions with CYP2D6 substrates have been systematically investigated, although concomitant use of such drugs was allowed in clinical trials with dextromethorphan hydrobromide and quinidine sulfate and in clinical trials with higher dose formulations of dextromethorphan/quinidine. Desipramine (CYP2D6 substrate): The tricyclic antidepressant desipramine is metabolized primarily by CYP2D6. A drug interaction study was conducted between a higher combination dose of dextromethorphan (dextromethorphan 30 mg/quinidine 30 mg) and desipramine 25 mg. The combination dose of dextromethorphan/quinidine increased steady state desipramine levels approximately 8-fold. If dextromethorphan hydrobromide and quinidine sulfate and desipramine are prescribed concomitantly, the initial dose of desipramine should be markedly reduced. The dose of desipramine can then be adjusted based on clinical response; however, a dose above 40 mg/day is not recommended. Paroxetine (CYP2D6 inhibitor and substrate): When the combination dose of dextromethorphan 30 mg/quinidine 30 mg was added to paroxetine at steady state, paroxetine exposure (AUC 0-24 ) increased by 1.7 fold and C max increased by 1.5 fold. Consideration should be given to initiating treatment with a lower dose of paroxetine if given with dextromethorphan hydrobromide and quinidine sulfate. The dose of paroxetine can then be adjusted based on clinical response; however, dosage above 35 mg/day is not recommended.

7.6 Digoxin Quinidine is an inhibitor of P-glycoprotein. Concomitant administration of quinidine with digoxin, a P-glycoprotein substrate, results in serum digoxin levels that may be as much as doubled. Plasma digoxin concentrations should be closely monitored in patients taking dextromethorphan hydrobromide and quinidine sulfate concomitantly, and the digoxin dose reduced, as necessary.

7.7 Alcohol As with any other CNS drug, caution should be used when dextromethorphan hydrobromide and quinidine sulfate is taken in combination with other centrally acting drugs and alcohol.

DRUG FACTS Active Ingredient (in each 5 mL cup)

Purpose

Guaifenesin, USP 100mg ..............................................................................................................................

Expectorant

Dextromethorphan HBr, USP 10mg ......................................................................................................

Cough Suppressant Active

Ingredient (in each 10 mL cup)

Purpose

Guaifenesin, USP 200mg ..............................................................................................................................

Expectorant

Dextromethorphan HBr, USP 20mg .......................................................................................................Cough Suppressant Inactive Ingredients Anhydrous citric acid, dextrose, FD&C Red No. 40, flavor, glycerin, high fructose corn syrup, menthol, purified water, saccharin sodium, sodium benzoate.

Inactive ingredients (Grape flavor) D&C red no. 30, FD&C blue no. 1, flavor, glycerin, high fructose corn syrup, methylparaben, polysorbate 80, polyvinyl acetate, povidone, propylparaben, purified water, sodium metabisulfite, sodium polystyrene sulfonate, sucrose, tartaric acid, tragacanth gum, triacetin, xanthan gum

Inactive ingredients (Orange flavor) D&C red no. 30, D&C yellow no. 10, flavor, glycerin, high fructose corn syrup, methylparaben, polysorbate 80, polyvinyl acetate, povidone, propylparaben, purified water, sodium metabisulfite, sodium polystyrene sulfonate, sucrose, tartaric acid, tragacanth gum, triacetin, xanthan gum