Ondansetron treatment in patients with Tourette's syndrome

Ondansetron, a selective 5-HT3 antagonist, may lower mesolimbic dopaminergi c hyperactivity. The present open-label pilot study evaluated the effect of ondansetron in Tourette's syndrome. Six Tourette's syndrome men aged 14-48 years resistant to haloperidol participated in the study. Assessments incl uded the Yale Global Tic Severity Scale (YGTSS), Yale-Brown Obsessive-Compu lsive Scale (Y-BOCS), and Tourette's syndrome-Clinical Global Impression (T S-CGI) scale. The maximal ondansetron dosage (8-16 mg per day) was given fo r 3 weeks. Ondansetron treatment was associated with a significant decrease in the severity of ties. Two patients showed a definite response (score im provement of 40% or more), and two showed a probable response ( > 25%). Two patients did not improve. Side-effects were transient and included abdomin al pain (n = 5) and constipation (n = 2). Ondansetron may possess anti-tie effects in some Tourette's syndrome patients. Int Clin Psychopharmacol 14:3 73-376 (C) 1999 Lippincott Williams & Wilkins.