Pharmacotherapy of generalized anxiety disorder: results of duloxetine treatment from a pooled analysis of three clinical trials

Objective: Duloxetine is a serotonergic noradrenergic reuptake inhibitor with demonstrated efficacy in each of three independent studies for treatment of adults with generalized anxiety disorder (GAD). A pooled dataset from all completed trials is provided here to show the most likely clinical outcomes associated with duloxetine treatment for GAD. Research design and methods: Data were summed at the individual patient level from three double-blind, placebo-controlled trials of duloxetine treatment: two were 10-week flexible-dose 60-120 mg/day and one was 9-week fixed dose 60 or 120 mg/day. Inclusion/exclusion criteria were consistent across studies. Main outcome measures: Efficacy measures included the Hamilton Anxiety Scale (HAMA) and Sheehan Disability Scale (SDS). Adverse events were queried at every visit in each study. Results: Patients were randomly assigned to duloxetine (n = 668) or placebo (n = 495) treatment. Mean age was 42.4 years; 65% were female. Duloxetine-treated patients improved significantly more from baseline to endpoint on HAMA total score (mean = -11.1 points) compared with placebo-treated patients (mean = -8.0 points, p <= 0.001). On the SDS global functioning score, patients in the duloxetine group had a mean improvement from baseline of 46% compared with 25% in the placebo group (p <= 0.001). Nausea was the most common of twelve treatment-emergent adverse events that occurred in the duloxetine group. Limitations: Pooled studies were not for long-term treatment and did not include patients with comorbid psychiatric conditions. Conclusions: In this sample of more than 1100 patients, duloxetine was efficacious for reducing anxiety severity and for increasing patients' overall role functioning in GAD.