Ondansetron Treatment of L-dopa-induced Psychosis

To the Editor: We read with interest the article of Zoldan et al. [1] reporting successful treatment of L-dopa-induced psychosis with the 5-HT3 receptor antagonist ondansetron (mean 18 mg/day, range 12 to 24 mg/day) in a short-term open label study of 16 parkinsonian patients. We wish to report our observations with open label ondansetron in seven parkinsonian patients with psychosis while on dopaminergic treatment, which suggest that an initial favorable effect is not always present and in addition may wane over a longer period. The mean age of our patients was 68 years, the mean duration of disease 10.3 years (range 56 to 72), the Hoehn and Yahr stage during their off phase ranged from two to five. All patients received L-dopa (mean dosage …