A case of risperidone overdose in early schizophrenia: a review of potential complications.

Deliberate drug overdose is a frequent occurrence in patients with schizophrenia. Typical antipsychotic medications can be lethal at doses 5 times the recommended therapeutic range. Clozapine, an atypical antipsychotic, can be toxic at doses 4 times a moderate dose. Little is known about the lethal effects of the novel antipsychotic risperidone, despite the fact that it is now one of the most widely prescribed antipsychotics in North America. To date, only 1 death attributable to risperidone overdose has been reported. The case presented here documents adverse cardiac effects in a 28-year-old man who intentionally ingested 24 mg of risperidone--4 times the recommended dose. A potential drug interaction with fluvoxamine and the role of active metabolites are discussed.