Purpose:
To evaluate the safety and efficacy of risperidone in patients with parkinson's disease (pd) who are experiencing significant dopamine-induced psychosis.
Patients and methods:
Seventeen patients (median age, 72 yrs) participated in this 12-week, open pilot study receiving 0.5 to 3 mg oral risperidone per day. maintenance antiparkinsonian medication was continued throughout, although psychotropic medication was discontinued. efficacy results: risperidone produced a substantial improvement in psychotic symptoms, shown on the mean total positive subscale score on the positive and negative syndrome scale (panss) by a 30% improvement (-3.1 decrease) after 1 week and a 66% improvement (-6.8 decrease) at end point. this improvement was most evident in the items delusions, hallucinatory behavior, and suspiciousness/persecution. risperidone also achieved significant improvement from baseline in clinical global impression (cgi)-severity and cgi-improvement (p < 0.001, page test). risperidone treatment did not adversely affect symptoms specific to parkinson's disease, as assessed by the unified parkinson's disease rating scale (updrs). safety results: sixteen patients reported at least one adverse event, but only two patients withdrew as a result of adverse events. no significant changes or clinically relevant abnormalities were observed in laboratory parameters or vital signs.
Conclusion:
Short-term use of risperidone (mean dosage, 1.1 mg per day) improves the psychopathology of patients with pd who have dopamine-induced psychosis without adversely affecting the symptoms of pd. higher doses and long-term use were not addressed in this study and may be precluded by extrapyramidal side effects.