Acute ingestion of doses in excess of 10 to 20 times the maximum therapeutic dose, have been reported, including fatal cases. Overdose has resulted in symptoms including nystagmus, ataxia, impaired consciousness, grand mal convulsion and coma. QRS broadening (intraventricular conduction delay) has also been observed in overdose patients.
In the event of overdosage, the patient should be admitted to the hospital and given appropriate supportive therapy as clinically indicated or as recommended by the national poisons centre, where available.