James T. Hartford

To conduct a post hoc evaluation of the prevalence of clinically significant pain and the efficacy of duloxetine in patients with generalized anxiety disorder (GAD) and concurrent pain. Data from two 9- to 10-week double-blind, placebo-controlled, randomized clinical trials of duloxetine (60 to 120 mg) in DSM-IV-defined GAD were analyzed (study 1 was conducted from July 2004 to September 2005; study 2 was conducted from August 2004 to June 2005). Efficacy was assessed with the Hamilton Rating Scale for Anxiety (HAM-A), visual analog scales (VAS) for pain, the Hospital Anxiety Depression Scale (HADS), the Clinical Global Impressions-Improvement of Illness (CGI-I) scale, the Patient Global Impressions-Improvement (PGI-I) scale, and the Sheehan Disability Scale (SDS) global functional impairment scale. Of 840 patients randomly assigned to treatment, 61.3% (302 duloxetine, 213 placebo) had VAS scores ≥ 30 mm on at least 1 of the pain scales, indicating clinically significant pain. Among those patients with concurrent pain at baseline, change from baseline to endpoint in the HAM-A total score (42.9% change in mean scores for duloxetine, 31.4% for placebo), HADS anxiety scale (40.3% vs. 22.8%), HADS depression scale (36.1% vs. 20.5%), HAM-A psychic factor (45.9% vs. 29.9%), and SDS global functional improvement score (45.5% vs. 22.1%) was significantly (all p's < .001) greater for duloxetine compared with placebo. Improvement on the CGI-I (p = .003) and PGI-I (p < .001) was also significantly greater for duloxetine. Response (HAM-A total score decrease ≥ 50%) (49% vs. 29%) and remission (HAM-A total score ≤ 7 at endpoint) (29% vs. 18%) rates were significantly greater for duloxetine compared with placebo (p < .001 and p = .041, respectively). Duloxetine demonstrated statistically significantly greater reduction in pain on all 6 VAS pain scales (all p's < .001 except headaches with p < .002) (for duloxetine, percent change in means from baseline to endpoint ranged from 40.1% to 45.2% across the 6 VAS scales; for placebo, 22.0% to 26.3%). Duloxetine, relative to placebo, improves anxiety symptoms, pain, and functional impairment among patients with GAD with concurrent clinically significant pain. clinicaltrials.gov Identifiers: NCT00122824 (study 1) and NCT00475969 (study 2).

This study examined the efficacy and tolerability of duloxetine 60-120 mg/day for the treatment of patients with generalized anxiety disorder. This was a multicenter, randomized, double-blind, flexible-dose, placebo and active-controlled (venlafaxine extended-release 75-225 mg/day) trial designed to assess duloxetine 60-120 mg/day during 10 weeks of treatment in adults with Diagnostic and statistical manual of mental disorders-IV-defined generalized anxiety disorder. The primary efficacy outcome measure was mean change from baseline to endpoint in the Hamilton Anxiety Rating Scale total score assessed using analysis of covariance. A total of 487 patients were randomly assigned to duloxetine (n=162), venlafaxine XR (n=164), or placebo (n=161). Significantly greater improvement on the Hamilton Anxiety Rating Scale total score occurred in the duloxetine (P=0.007) and venlafaxine XR (P<0.001) groups compared with the placebo group. Overall discontinuation rates did not differ among the three groups, but adverse event-related discontinuation was significantly higher in the duloxetine (14.2%, P<0.001) and venlafaxine XR (11.0%, P=0.001) groups than in the placebo group (1.9%). During the 2-week drug-tapering phase, discontinuation-emergent adverse events were significantly greater in the venlafaxine XR group (26.9%, P=0.04), but not in the duloxetine group (19.4%, P=0.448) compared with placebo (15.8%). Duloxetine 60-120 mg/day and venlafaxine XR 75-225 mg/day were each efficacious treatments for patients with generalized anxiety disorder.