TRIMETHOBENZAMIDE Drug Interactions: What You Need to Know

INTERACTIONS

• Alcohol : May cause drowsiness; avoid concomitant use. ( 7.1 )
• Other Drugs that Cause CNS Depression or EPS : Either trimethobenzamide hydrochloride capsules or the other interacting drug should be chosen, depending on the importance of the drug to the patient. If CNS-acting drugs cannot be avoided, monitor patients for CNS adverse reactions. ( 7.2 )

7.1 Alcohol Alcohol may increase the CNS depressant effects of trimethobenzamide hydrochloride capsules and may cause drowsiness <span class="opacity-50 text-xs">[see Warnings and Precautions ( 5.3 , 5.5 )]</span>. Avoid concomitant use of trimethobenzamide hydrochloride capsules with alcohol.

7.2 Other Drugs that Cause CNS Depression or EPS The concurrent use of trimethobenzamide hydrochloride capsules with other drugs that cause CNS depression or EPS (e.g., sedatives, hypnotics, opiates, anxiolytics, antipsychotics, and anticholinergics, may potentiate the effects of trimethobenzamide hydrochloride capsules <span class="opacity-50 text-xs">[see Warnings and Precautions ( 5.1 , 5.2 , 5.3 , 5.5 )]</span> . Either trimethobenzamide hydrochloride capsules or the other interacting drug should be chosen, depending on the importance of the drug to the patient. If CNS-acting drugs cannot be avoided, monitor patients for CNS adverse reactions.

Contraindications The injectable form of Tigan ® is contraindicated in pediatric patients and in patients with known hypersensitivity to trimethobenzamide.

Contraindications

The injectable form of Tigan ® is contraindicated in pediatric patients and in patients with known hypersensitivity to trimethobenzamide.

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 <span class="opacity-50 text-xs">[see Dosage and Administration (2.1) ]</span> . Avoid trimethobenzamide hydrochloride capsules in patients receiving other drugs that are likely to cause EPS (e.g. antipsychotics) <span class="opacity-50 text-xs">[see Drug Interactions (7.2) ]</span> .

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&apos;s syndrome)) <span class="opacity-50 text-xs">[see Warnings and Precautions ( 5.1 , 5.3 )]</span>. 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 <span class="opacity-50 text-xs">[see Warnings and Precautions (5.1 , 5.5 )]</span>. Consider reducing the daily dosage of trimethobenzamide hydrochloride capsules by increasing the dosing interval or discontinuing the drug <span class="opacity-50 text-xs">[see Dosage and Administration (2.1) , Drug Interactions (7.1 , 7.2 )]</span> .

5.4 Hepatotoxicity Trimethobenzamide hydrochloride capsules is potentially hepatotoxic <span class="opacity-50 text-xs">[see Adverse Reactions (6) ]</span> . Avoid use of trimethobenzamide hydrochloride capsules in patients whose signs and symptoms suggest the presence of hepatic impairment . Discontinue trimethobenzamide hydrochloride capsules in patients who develop impaired liver function while taking trimethobenzamide hydrochloride capsules.

5.5 Effects on the Ability to Drive or Operate Machinery Trimethobenzamide hydrochloride capsules can cause drowsiness and may impair the mental and/or physical abilities required for the performance of hazardous tasks such as driving a motor vehicle or operating machinery <span class="opacity-50 text-xs">[see Warnings and Precautions (5.1 , 5.3 )]</span> . Concomitant use of other drugs that cause CNS depression or EPS symptoms (e.g., alcohol, sedatives, hypnotics, opiates, anxiolytics, antipsychotics, and anticholinergics) 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 [ Drug Interactions (7.1 , 7.2 )]. Inform patients not to operate motor vehicles or other dangerous machinery until they are reasonably certain that trimethobenzamide hydrochloride capsules does not affect them adversely.