Safety and tolerability of aripiprazole in patients with psychosis associated with Parkinson's disease—Results of a multicenter open trial

AIM: To evaluate the effect of aripiprazole on psychosis and motor function in Japanese Parkinson's disease patients. METHODS: Patients with Parkinson's disease and hallucinations and/or delusions were enrolled. They were administered aripiprazole 3 mg/day, with dosage increased or reduced as needed. Patients were evaluated using the Brief Psychiatric Rating Scale (BPRS), Clinical Global Impression‐Severity (CGI‐S) scale, and Clinical Global Impression‐Improvement scale for psychiatric response; Hoehn & Yahr staging and Unified Parkinson's Disease Rating Scale (UPDRS) part III for motor response; Mini‐Mental State Examination (MMSE) and Frontal Assessment Battery (FAB) for cognitive response; and Schwab and England Activities of Daily Living scale for daily activities of patients, before and at 2, 4, and 12 weeks after initiation of open‐label aripiprazole administration. This study was registered at the University Hospital Medical Information Network Center (registration number: UMIN000007711). RESULTS: Nine of the 24 enrolled patients discontinued the study. Among them, eight patients discontinued the trial on account of their worsening parkinsonian symptoms. There were no differences in age, disease duration, disease severity, and MMSE and FAB scores at baseline between patients who continued and discontinued the study. However, in patients who continued aripiprazole administration at 3 mg/day or less significantly improved BPRS, CGI‐S scale, and UPDRS parts I and III scores. CONCLUSION: Significant improvements in hallucinations and delusions can be expected, although aripiprazole may aggravate parkinsonism in Parkinson's disease patients. Low‐dose use of aripiprazole may be useful for managing Parkinson's disease patients with psychosis, but only with close observation of extrapyramidal symptoms.