OBJECTIVE: There is a need to identify novel pharmacotherapies for anxiety disorders. The authors examined the safety and efficacy of riluzole, an antiglutamatergic agent, in adult outpatients with generalized anxiety disorder. METHOD: In an 8-week, open-label, fixed-dose study, 18 medically healthy patients with DSM-IV generalized anxiety disorder received treatment with riluzole (100 mg/day) following a 2-week drug-free period. The primary efficacy measure was the Hamilton Anxiety Rating Scale (HAM-A) score at endpoint. RESULTS: Twelve of the 15 patients who completed the trial responded positively to riluzole. At 8 weeks, eight of the 15 patients had HAM-A score indicating remission of their anxiety. The median time to response was 2.5 weeks. CONCLUSIONS: Riluzole appears to be an effective, well-tolerated, and rapidly acting anxiolytic medication for some patients with generalized anxiety disorder. Larger, placebo-controlled studies are indicated.