Background: Duloxetine is approved for the treatment of generalized anxiety disorder (GAD) in the United States and elsewhere. This study aimed to assess the efficacy, tolerability, and safety of duloxetine in Chinese patients with GAD.
Methods: This 9-site study consisted of double-blind treatment for 15 weeks either with duloxetine 60 - 120 mg or with placebo. Patients with at least moderately severe GAD and a Sheehan Disability Scale (SDS) global functioning impairment total score ≥ 12 were included in this study. Patients who were randomly assigned to duloxetine received 60 mg for 7 weeks; at that point, for nonresponders the dose was increased to 120 mg for the remaining 8 weeks. The primary efficacy measure was mean change from baseline to endpoint on the Hospital Anxiety and Depression Scale-Anxiety subscale score (HADS-A). Secondary efficacy measures included the Hamilton Anxiety Rating Scale (HAMA), the SDS, and pain measures. Safety and tolerability were assessed.
Results: Baseline characteristics did not differ significantly between treatment groups. Mean age of the subjects (n = 210) was 37.6 years, 50.5% were female, and 74.3% completed the 15 weeks treatment. Patients treated with duloxetine had significantly greater improvement compared to placebo on the HADS-A (mean change -6.6 vs. -4.9, respectively, P = 0.022). Improvement in anxiety was greater with duloxetine treatment at 7 weeks and continued through 15 weeks for both the HADS-A and the HAMA total score (0.01 ≤ P < 0.05). Compared with placebo, duloxetine was also associated with greater improvement on most secondary measures, but not on the SDS global functioning score. Nausea, dizziness, and somnolence occurred significantly more frequently as treatment-emergent adverse events with duloxetine treatment compared with placebo treatment.
Conclusions: Duloxetine 60 - 120 mg once daily is effective and well-tolerated for the treatment of patients with GAD in China.
Trial registration: ClinicalTrials.gov NCT00803361.