Efficacy of duloxetine for the treatment of generalized anxiety disorder: implications for primary care physicians

Abstract

Objective: This study examined the efficacy and tolerability of duloxetine, a dual reuptake inhibitor of serotonin and norepinephrine, for the treatment of patients with generalized anxiety disorder (GAD).

Method: Patients were ≥ 18 years old and recruited from 5 European countries, the United States, and South Africa. The study had a 9-week, multicenter, randomized, double-blind, fixed-dose, placebo-controlled, parallel-group design. A total of 513 patients (mean age = 43.8 years; 67.8% female) with a DSM-IV-defined GAD diagnosis received treatment with duloxetine 60 mg/day (N = 168), duloxetine 120 mg/day (N = 170), or placebo (N = 175). The primary efficacy measure was the Hamilton Rating Scale for Anxiety (HAM-A) total score. Secondary measures included the Sheehan Disability Scale, HAM-A psychic and somatic anxiety factor scores, and HAM-A response, remission, and sustained improvement rates. The study was conducted from July 2004 to September 2005.

Results: Both groups of duloxetine-treated patients demonstrated significantly greater improvements in anxiety symptom severity compared with placebo-treated patients as measured by HAM-A total score and HAM-A psychic and somatic anxiety factor scores (p values ranged from ≤ .01 to ≤ .001). Duloxetine-treated patients had greater functional improvements in Sheehan Disability Scale global and specific domain scores (p ≤ .001) than placebo-treated patients. Both duloxetine doses also resulted in significantly greater HAM-A response, remission, and sustained improvement rates compared with placebo (p values ranged from ≤ .01 to ≤ .001). The rate of study discontinuation due to adverse events was 11.3% for duloxetine 60 mg and 15.3% for duloxetine 120 mg versus 2.3% for placebo (p ≤ .001).

Conclusion: The results of this study demonstrate that duloxetine 60 mg/day and 120 mg/day were efficacious and well tolerated and thus may provide primary care physicians with a useful pharmacologic intervention for GAD.

Clinical trials registration: ClinicalTrials.gov identifier NCT00122824.

Figures

Figure 1.

Mean Change From Baseline to Endpoint in HAM-A Total Score by Treatment Week (MMRM) and at Endpoint (week 9, LOCF)

Figure 2.

Change From Baseline to Endpoint on the Sheehan Disability Scale Global Functional Impairment and Specific Domain Scores by Treatment Group

Figure 3.

Adverse Events That Had an Incidence ≥ 5% for Duloxetine and Were at Least Twice as Frequent as for Placebo

Figure 4.

Discontinuation-Emergent Adverse Events During Drug-Tapering Phase