Quetiapine fumarate extended-release for the treatment of major depression with comorbid fibromyalgia syndrome: a double-blind, randomized, placebo-controlled study.

Objective Fibromyalgia and major depressive disorder (MDD) frequently co-occur. Quetiapine fumarate extended-release (quetiapine XR) has demonstrated efficacy in the treatment of MDD and has been shown to have analgesic properties in patients with depression. The primary objectives of this study were to evaluate the effects of quetiapine XR on depressive and pain symptoms in patients with MDD and comorbid fibromyalgia, and to assess its safety and tolerability. Methods This was an 8-week, single-center, double-blind, randomized, controlled trial. A total of 120 nonpsychotic adult outpatients who fulfilled the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition diagnostic criteria for MDD and whose diagnosis of fibromyalgia was confirmed according to the American College of Rheumatology criteria were enrolled. The primary end point was the mean change from baseline to week 8 on the 17-item Hamilton Depression Rating (HAM-D) scale. Secondary end points included other depression-rating scores, pain scores, fibromyalgia scores, measures of quality of life and global functioning, and adverse events. Results The mean change in the HAM-D score from baseline to week 8 was significantly greater in the quetiapine XR group compared with the placebo group (−10.0 versus −5.8; P = 0.001). Improvements in most secondary outcomes were also significantly greater in the quetiapine XR group. Quetiapine XR was generally well tolerated. Conclusion This study is the first to demonstrate that measures of depression, pain, and quality of life are significantly improved with quetiapine XR compared with placebo in patients with a dual diagnosis of MDD and fibromyalgia.