Objective: To assess the efficacy and tolerability of quetiapine for agitation or psychosis in patients with dementia and parkinsonism.
Methods: Multicenter randomized, double-blind, placebo-controlled parallel groups clinical trial involving 40 patients with dementia with Lewy bodies (n = 23), Parkinson disease (PD) with dementia (n = 9), or Alzheimer disease with parkinsonian features (n = 8). The main outcome measure for efficacy was change in the Brief Psychiatric Rating Scale (BPRS) from baseline to 10 weeks of therapy. For tolerability it was change in the Unified PD Rating Scale (UPDRS) motor section over the same time period. The trial was confounded by the need for a design change and incomplete recruitment.
Results: No significant differences in the primary or secondary outcome measures of efficacy were observed. An unexpectedly large placebo effect, inadequate dosage (mean 120 mg/day), and inadequate power may have contributed to lack of demonstrable benefit. Quetiapine was generally well-tolerated and did not worsen parkinsonism, but was associated with a trend toward a decline on a measure of daily functioning.
Conclusions: Quetiapine was well-tolerated and did not worsen parkinsonism. Although conclusions about efficacy may be limited, the drug in the dosages used did not show demonstrable benefit for treating agitation or psychosis in patients with dementia and parkinsonism. These findings are in keeping with prior studies reporting limited efficacy of various medications for reducing behavioral problems in demented patients.