Clozapine for the treatment of levodopa-induced psychosis and dyskinesia in Parkinson's disease

Abstract

AbstractThe treatment of psychosis in patients with Parkinson's disease (PD) is one of the most difficult problems in clinical psychiatry. Clozapine's low propensity to induce extrapyramidal side effects makes it an attractive treatment for psychotic patients with PD. A number of published uncontrolled studies suggest that low-dose clozapine is effective in these patients. However, the dose range, side effect profiles and length of treatment have varied in these reports. In this article, the authors review the literature and report on the effects of clozapine in a patient with Parkinson's disease and psychosis. Clozapine (50mg per day) resulted in a complete resolution of psychosis, improvement of motor function, reduction of “off” time and a major improvement in levodopa-induced dystonic dyskinesias. The only adverse effect was mild sedation during the first two weeks of clozapine treatment. The lack of acute blockade of striatal D2 receptors by clozapine and the failure of chronic clozapine treatment to suppress striatal dopamine release may account for its beneficial effect in Parkinson's disease. Additionally, an ameliorating effect of clozapine on parkinsonism might be due to its action on serotonergic systems leading to release of striatal dopamine.