5 WARNINGS AND PRECAUTIONS
5.1 Acute Dystonic Reactions and Other Extrapyramidal Symptoms (EPS)
Extrapyramidal symptoms (EPS), manifested primarily as acute dystonic reactions, may occur with Tigan. 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 Tigan by increasing the dosing interval or discontinue Tigan [see Dosage and Administration (2.1)].
Avoid Tigan 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 Tigan 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 Tigan 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 Tigan 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 Tigan by increasing the dosing interval or discontinuing the drug [see Dosage and Administration (2.1), Drug Interactions (7.1, 7.2)].
Tigan is potentially hepatotoxic [see Adverse Reactions (6)]. Avoid use of Tigan in patients whose signs and symptoms suggest the presence of hepatic impairment. Discontinue Tigan in patients who develop impaired liver function while taking Tigan.
5.5 Effects on the Ability to Drive or Operate Machinery
Tigan 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 [see Warnings and Precautions (5.1, 5.3)]. 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 Tigan 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 Tigan does not affect them adversely.