A multicenter investigation of fixed-dose fluoxetine in the treatment of obsessive-compulsive disorder.

Objectives: To determine the effectiveness of fluoxetine hydrochloride at fixed doses of 20 mg/d, 40 mg/d, and 60 mg/d in patients with obsessive-compulsive disorder (OCD) and to evaluate its safety.
Methods: Fixed-dose fluoxetine hydrochloride (20 mg/d, 40 mg/d, 60 mg/d) was compared with placebo in two randomized, double-blind, parallel, 13-week trials of identical design in 355 outpatients with OCD aged 15 to 70 years (DSM-III-R criteria; 1 year's duration or longer; depression secondary if present).
Results: Fluoxetine (all doses) was significantly (P < or = .001) superior to placebo on the Yale-Brown Obsessive Compulsive Scale (Y-BOCS) total score (mean baseline-to-end-point decrease, 4.6, 5.5, and 6.5 vs 0.9, respectively, studies pooled) and other efficacy measures (P < or = .01). A trend suggesting greater efficacy at 60 mg/d was observed. Most patients (79.2%) completed the study. Eight adverse events were statistically significantly more frequent with fluoxetine and one, with placebo. For some events, incidence tended to increase with increasing dosage; however, few patients discontinued treatment for any single event.
Conclusion: Fluoxetine was associated with a statistically significant reduction in OCD severity, including time engaged in obsessional and/or compulsive behaviors. Adverse events infrequently led to study discontinuation.