Efficacy of extended-release venlafaxine in nondepressed outpatients with generalized anxiety disorder

Objective: This study evaluated the efficacy and safety of fixed doses of once daily extended-release (XR) venlafaxine in outpatients with generalized anxiety disorder without concomitant major depressive disorder. Method: Adult outpatients with generalized anxiety disorder but not major depressive disorder with total scores of 18 or higher on the Hamilton Rating Scale for Anxiety and scores of 2 or higher on its anxious mood and tension factors were eligible. Patients were randomly assigned to receive placebo or venlafaxine XR (75, 150, or 225 mg/day) for 8 weeks. Primary efficacy variables were final total and psychic anxiety factor scores on the Hamilton anxiety scale and final severity and global improvement item scores on the Clinical Global impression (CGI) scale. Results: Of the 377 patients entering the study, 370 were included in a safety analysis and 349 in an efficacy analysis. Adjusted mean scores at 8 weeks (last-observation-carried-forward analysis) were significantly lower for one or more of the venlafaxine XR groups in four of four primary and three of four secondary outcome measures than for the placebo group. These included a change of 1.7 (versus 1.3) from baseline on CGI severity item scores and a final score of 2.2 (versus 2.6) on the CGI global improvement item. All doses of venlafaxine XR were well tolerated. Conclusions: Venlafaxine XR is an effective and well-tolerated option for the short-term treatment of generalized anxiety disorder in outpatients without major depressive disorder.