Priapism associated with two atypical antipsychotic agents.

Priapism has been associated with many antipsychotic agents, including clozapine, risperidone, and olanzapine. This prolonged, usually painful, penile erection rarely results from the alpha-adrenergic blocking action of antipsychotics. A 22-year-old African-American man developed priapism during treatment with risperidone and, on a later occasion, during treatment with ziprasidone. The problem resolved only with substitution of other drugs for these antipsychotics. Certain patients may be more vulnerable than others to this adverse effect. Clinicians must be aware of such complications and use caution when prescribing these drugs.