Background: The American Academy of Neurology considers clozapine first line treatment for psychosis in Parkinson's disease (PD). In practice, patients are typically treated with quetiapine initially despite only level C evidence for use due to concern about side-effects, and changed to clozapine if they fail this.
Aim: To review the use of antipsychotics in patients with PD and the demographics of PD patients who develop psychosis.
Methods: Patients with PD on antipsychotic medications were identified by the Movement Disorder Nurse Specialist database and by reviewing patients admitted to Auckland City Hospital from January 2006 until March 2008. The demographic data, details of PD and antipsychotic use and comorbidities were recorded.
Results: Sixty-six patients with PD on antipsychotics were identified. The mean age was 75 years and 48 (73%) were in residential care. Patients admitted on antipsychotics had longer disease duration (P < 0.001) and were more likely to have cognitive impairment (P= 0.02) than those admitted not on antipsychotics. The most common indication for use was hallucinations. Patients on clozapine were younger (P < 0.005) and had less comorbidity (P= 0.04) than those on quetiapine. Fifty per cent (6/12) of patients on clozapine had previously failed quetiapine.
Conclusion: Quetiapine has a good efficacy rate with minimal side-effects. This study lends support to the assumption that quetiapine is a useful medication. However, clozapine also was well tolerated and could be considered for use more frequently than it is.