Recurrent Priapism During Treatment With Clozapine and Olanzapine

Mr. A was a 43-year-old man diagnosed with schizoaffective disorder of the bipolar type. He began clozapine therapy for refractory psychosis, which resulted in near-complete remission of his psychotic symptoms. However, he later experienced two episodes of prolonged painful erection, which lasted approximately 12.0 and 13.5 hours. Mr. A’s clozapine treatment was discontinued, and during the next 2 years his condition was stabilized with olanzapine, divalproex, and thiothixene. His medical records indicated that an adequate response was not achieved with the combination of divalproex and olanzapine or divalproex and thiothixene.

Mr. A was then hospitalized for exacerbation of his psychosis. He had been noncompliant with his psychotropic treatment for 3 weeks before admission. At admission, his treatment regimen was reinitiated, as previously prescribed, with 25 mg/day of olanzapine, 1000 mg/day of divalproex, and 5 mg/day of thiothixene. The next morning he awoke with a painful erection. With conservative drug management, the priapistic episode began to remit after 5 hours. Mr. A’s penis returned to normal flaccidity after 8 to 10 hours. His dose of olanzapine was discontinued, and he was stabilized with 25 mg/day of thiothixene. This adverse event was reported to the manufacturer and the Food and Drug Administration.