Clozapine treatment of psychosis in Parkinson's disease: a report of five consecutive cases

Abstract

Background: Clozapine has gained acceptance as an antipsychotic in treatment-resistant schizophrenia. Its low propensity to induce extrapyramidal side effects makes clozapine an attractive treatment for patients with Parkinson's disease and dopaminomimetic psychosis. Recent evidence demonstrates that Parkinson's patients are exquisitely sensitive to both the antipsychotic and the potential extrapyramidal effects of clozapine. The uncontrolled studies suggest that low-dose clozapine may be efficacious in this population. The dose range, side effect profiles, and length of treatment varied in these reports.

Method: We report our experience with five patients with Parkinson's disease and psychosis who were treated with clozapine in an open trial.

Results: Three patients were successfully treated with clozapine (25-100 mg/day, mean = 66.7 mg) without worsening their parkinsonism. Adverse effects unrelated to the motor disability required discontinuation of clozapine in the other two patients. At 1- to 2-year follow-up, each patient had required increased dosages of clozapine (75-150 mg/day, mean = 125 mg) for continued management of their psychosis and parkinsonism. The higher dose range was well tolerated.

Conclusion: These results suggest that clozapine may effectively treat psychosis in Parkinson's disease.