Trimethobenzamide

1 INDICATIONS AND USAGE Trimethobenzamide hydrochloride capsules is indicated in adults for the treatment of postoperative nausea and vomiting and for nausea associated with gastroenteritis. Limitation of Use: Trimethobenzamide hydrochloride capsules is not recommended for use in pediatric patients due to the risk of extrapyramidal signs and symptoms and other serious central nervous system (CNS) effects, and the risk of exacerbation of the underlying disease in pediatric patients with Reye's syndrome or other hepatic impairment. Trimethobenzamide hydrochloride capsules are an antiemetic indicated in adults for the treatment of postoperative nausea and vomiting and for nausea associated with gastroenteritis. ( 1 ) Limitation of Use: • Trimethobenzamide hydrochloride capsules are not recommended for use in pediatric patients due to the risk of extrapyramidal signs and symptoms and other serious central nervous system (CNS) effects and the risk of exacerbation of the underlying disease in pediatric patients with Reye's syndrome or other hepatic impairment. ( 1 , 8.4 )

12.1 Mechanism of Action The mechanism of action of trimethobenzamide as determined in animals is obscure, but may involve the chemoreceptor trigger zone (CTZ), an area in the medulla oblongata through which emetic impulses are conveyed to the vomiting center; direct impulses to the vomiting center apparently are not similarly inhibited. In dogs pretreated with trimethobenzamide HCl, the emetic response to apomorphine is inhibited, while little or no protection is afforded against emesis induced by intragastric copper sulfate.

2 DOSAGE AND ADMINISTRATION • The recommended adult dosage is 300 mg orally three or four times daily. ( 2.1 ) • Geriatric patients and/or patients with renal impairment (creatinine clearance 70 mL/min/1.73m2 or less): Reduce the daily dosage by increasing the dosing interval; monitor renal function. ( 2.2 , 8.5 , 8.6 ) • Select the lowest effective daily dosage and adjust as needed based upon therapeutic response and tolerability. ( 2.1 , 2.2 ) 2.1 Recommended Adult Dosage The recommended adult dosage is 300 mg orally three or four times daily. Select the lowest effective daily dosage and adjust as needed based upon therapeutic response and tolerability. 2.2 Dosage Adjustment for Geriatric Patients and/or Patients with Renal Impairment In geriatric patients and/or in patients with renal impairment (creatinine clearance 70 mL/min/1.73m2 or less), reduce the daily dosage of trimethobenzamide hydrochloride capsules by increasing the dosing interval and adjust as needed based upon therapeutic response and tolerability. Monitor renal function [see Use in Specific Populations ( 8.5 , 8.6 )] .

6 ADVERSE REACTIONS The following adverse reactions from voluntary reports or clinical studies have been reported with trimethobenzamide. Because many of these reactions were 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. Nervous system disorders: Parkinson-like symptoms, coma, convulsions, opisthotonos, dizziness, drowsiness, headache, [see Warnings and Precautions ( 5.1 , 5.2 , 5.3 )] Psychiatric disorders: disorientation, depression of mood Eye disorders: blurred vision Hematologic disorders: blood dyscrasias Hepatobiliary disorders: jaundice [see Warnings and Precautions ( 5.4 )] Immune system disorders: hypersensitivity, including angioedema and allergic-type skin reactions Gastrointestinal disorders: diarrhea Musculoskeletal disorders: muscle cramps Adverse reactions include hypersensitivity reactions and Parkinson-like symptoms; blood dyscrasias, blurring of vision, coma, convulsions, depression of mood, diarrhea, disorientation, dizziness, drowsiness, headache, jaundice, muscle cramps, and opisthotonos. ( 6 ) To report SUSPECTED ADVERSE REACTIONS, contact Lupin Pharmaceuticals, Inc. at 1-866-403-7592 or FDA at 1-800-FDA-1088 or WWW.FDA.GOV/MEDWATCH .

5 WARNINGS AND PRECAUTIONS Acute Dystonic Reactions and Other Extrapyramidal Symptoms (EPS) : Depending on the severity of symptoms, reduce the dosage or discontinue the drug. Treat acute dystonic reactions with anticholinergics. Avoid trimethobenzamide hydrochloride capsules in patients receiving other drugs that are likely to cause EPS. ( 5.1 , 7.2 ) Masking of Other Serious Disorders : EPS and other CNS symptoms in patients treated with trimethobenzamide hydrochloride capsules may be confused with CNS signs of undiagnosed primary disease (e.g., encephalopathy, metabolic imbalance, Reye's Syndrome). If CNS symptoms occur, evaluate the risks and benefits of continuing trimethobenzamide hydrochloride capsules. ( 5.2 , 7.2 ) Other CNS Reactions : Coma, depression of mood, disorientation, and seizures have been reported. The recent use of other drugs that cause CNS depression or EPS symptoms may also increase the risk; consider reducing the dosage or discontinuing the drug. ( 5.3 , 7.1 , 7.2 ) Hepatotoxicity : Avoid use in patients whose signs and symptoms suggest the presence of hepatic impairment. Discontinue trimethobenzamide hydrochloride capsules in patients who develop impaired liver function while on treatment. ( 5.4 , 8.7 ) Effects on the Ability to Drive or Operate Machinery : Mental and/or physical abilities may be impaired. Concomitant use of other drugs that cause CNS depression or EPS symptoms may increase this effect; either trimethobenzamide hydrochloride capsules or the other interacting drug should be chosen, depending on the importance of the drug to the patient. ( 5.5 , 7.1 , 7.2 ) 5.1 Acute Dystonic Reactions and Other Extrapyramidal Symptoms (EPS) Extrapyramidal symptoms (EPS), manifested primarily as acute dystonic reactions, may occur with trimethobenzamide hydrochloride capsules. Dystonic reactions may include sudden onset of muscular spasms, especially in the head and neck or opisthotonos. Other EPS include laryngospasm, dysphagia, and oculogyric crisis. Involuntary spasms of the tongue and mouth may lead to difficulty in speaking and swallowing. Anticholinergic drugs can be used to treat acute dystonic reactions. EPS may also include akathisia, restlessness, akinesia, and other parkinsonian-like symptoms (e.g., tremor). Depending on the severity of symptoms, reduce the daily dosage of trimethobenzamide hydrochloride capsules by increasing the dosing interval or discontinue trimethobenzamide hydrochloride capsules [see Dosage and Administration (2.1) ] . Avoid trimethobenzamide hydrochloride capsules in patients receiving other drugs that are likely to cause EPS (e.g. antipsychotics) [see Drug Interactions (7.2) ] . 5.2 Masking of Other Serious Disorders EPS and other CNS symptoms which can occur in patients treated with trimethobenzamide hydrochloride capsules may be confused with CNS signs of undiagnosed primary disease (e.g., encephalopathy, metabolic imbalance, Reye's syndrome)) [see Warnings and Precautions ( 5.1 , 5.3 )]. If CNS symptoms occur, evaluate the risks and benefits of continuing trimethobenzamide hydrochloride capsules for each patient. 5.3 Other CNS Reactions Other serious CNS adverse reactions such as coma, depression of mood, disorientation, and seizures have been reported with trimethobenzamide hydrochloride capsules administration. The recent use of other drugs that cause CNS depression or EPS symptoms (e.g., alcohol, sedatives, hypnotics, opiates, anxiolytics, antipsychotics, and anticholinergics) may also increase the risk for these serious CNS reactions [see Warnings and Precautions (5.1 , 5.5 )]. Consider reducing the daily dosage of trimethobenzamide hydrochloride capsules by increasing the dosing interval or discontinuing the drug [see Dosage and Administration (2.1) , Drug Interactions (7.1 , 7.2 )] . 5.4 Hepatotoxicity Trimethobenzamide hydrochloride capsules is potentially hepatotoxic [see Adverse Reactions (6) ] . Avoid use of trimethobenzamide hydrochloride capsules in pa

4 CONTRAINDICATIONS Trimethobenzamide hydrochloride capsules are contraindicated in patients with known hypersensitivity to trimethobenzamide [see Adverse Reactions ( 6 )] . Known hypersensitivity to trimethobenzamide ( 4 )