Riluzole in augmentation of fluvoxamine for moderate to severe obsessive-compulsive disorder: Randomized, double-blind, placebo-controlled study.

Aim: The aim of the present randomized, double-blind, placebo-controlled, 8-week trial was to assess the efficacy and tolerability of riluzole augmentation of fluvoxamine in treatment of patients with moderate to severe obsessive-compulsive disorder.

Methods: Patients were randomized into two parallel groups to receive fluvoxamine plus placebo or fluvoxamine plus riluzole (50 mg twice daily). All patients, regardless of their treatment group, received fluvoxamine at 100 mg/day for the initial 4 weeks of the study followed by 200 mg/day of fluvoxamine for the rest of the trial course. A total of 50 patients (25 in each group) were evaluated for response to treatment using the Yale-Brown Obsessive Compulsive Scale (Y-BOCS) at baseline and at weeks 4, 8 and 10. Side-effects were recorded using predesigned checklists in each visit. Repeated-measure analysis of variance showed a significant effect for time × treatment interaction in the Y-BOCS total score and a significant effect for time × treatment interaction in the Y-BOCS Compulsive subscale score between the two groups.

Results: Repeated-measure analysis of variance showed a significant effect for time × treatment interaction (Greenhouse-Geisser corrected: F = 4.07, d.f. = 1.22, P = 0.04) in the Y-BOCS total score and a significant effect for time × treatment interaction (Greenhouse-Geisser corrected: F = 4.45, d.f. = 1.33, P = 0.028) in the Y-BOCS Compulsive subscale score between the two groups. Riluzole augmentation therapy demonstrated higher, partial or complete treatment response according to the Y-BOCS total scores.

Conclusion: Riluzole may be of clinical use as an adjuvant agent to fluvoxamine in treatment of moderate to severe obsessive-compulsive disorder.