Objective: To compare the efficacy and safety of ziprasidone versus clozapine in patients with psychotic symptoms in Parkinson disease.
Methods: A 4-week, randomized, single-blind, open-label, parallel comparison of ziprasidone and clozapine was completed. Sixteen patients with Parkinson disease were included. Psychosis was assessed using the Brief Psychiatric Rating Scale (BPRS), and the Scale for the Assessment of Positive Symptoms (SAPS). The Unified Parkinson's Disease Rating Scale and the Abnormal Involuntary Movement Scale were used to assess motor conditions during the study period. Measures of drugs' adverse effects, white blood cell count, and the Clinical Global Impression Scale-Severity Subscale were performed. Cognitive changes were assessed with the Mini-Mental State Examination.
Results: Fourteen patients completed the study, 8 patients on clozapine and 6 patients on ziprasidone. The final mean dosage for clozapine was 32.14 mg/d and that for ziprasidone was 35 mg/d. Throughout the study, neither the Unified Parkinson's Disease Rating Scale, the Abnormal Involuntary Movement Scale, or the Mini-Mental State Examination showed statistical differences in both groups. Psychotic symptoms, assessed with SAPS and BPRS, were reduced in both groups but with more intensity in the ziprasidone group (effect size in SAPS, 1.3, and effect size in BPRS, 1.7) than in the clozapine group (effect size in SAPS, 0.36, and effect size in BPRS, 0.53).
Conclusions: Ziprasidone seems to be at least as effective as clozapine in the treatment to ameliorate psychotic symptoms in PD.