Low-dose olanzapine for levodopa induced dyskinesias

Objective: To assess the usefulness of low-dose olanzapine (2.5 to 7.5 mg/d ay) for Levodopa-induced-dyskinesias (LID) in patients with PD. Methods: Te n patients with PD and LID took part in this randomized, placebo-controlled , double blind, crossover trial. Patients received a 2-week course of olanz apine or placebo in each treatment phase with 1-week washout in between. Dy skinesias were assessed at baseline and after each treatment period with an acute dopaminergic challenge and unified PD rating scale (UPDRS) questionn aires. Patients also kept on/off and dyskinesia diaries for the last 3 days prior to each assessment. Results: There was a 41% difference in dyskinesi a reduction on olanzapine compared to placebo, as measured by objective dys kinesia rating scales (mean percentage reduction abnormal involuntary movem ent score: 30% versus -11.2%, p < 0.02). Similar differences were demonstra ted by patient diaries (mean reduction: 46% versus -2%, p < 0.02) and UPDRS items 32 and 33. Compared with placebo, treatment with olanzapine resulted in significant increases in 'off' time as measured by patient diaries (30% versus 2%) and reported adverse events (1.7 versus 0.1) including increase d parkinsonism (1.1 versus 0.1) and a nonsignificant reported increase in d rowsiness. Conclusions: Low-dose olanzapine is effective in reducing dyskin esias in PD, but even at very low doses can result in unacceptable increase s in parkinsonism and 'off' time.