<p>There is no clinical experience with massive overdose. Symptoms of overdose are nausea, vomiting, hyperkinesia, hallucinations, agitation and hypotension. There is no established antidote. If signs of central nervous system stimulation are present, a neuroleptic agent may be indicated. Management of the overdose may require general supportive measures, along with gastric lavage, intravenous fluids, administration of activated charcoal and electrocardiogram monitoring.</p>