Efficacy and safety of duloxetine 60 mg once-daily in patients with chronic low back pain

Duloxetine, a reuptake inhibitor of serotonin and norepinephrine, is effective in the treatment of diabetic peripheral neuropathic pain, fibromyalgia, and pain associated with osteoarthritis. We report here the efficacy of duloxetine in patients with chronic low back pain (CLBP). Adult patients (N = 401) with non-neuropathic CLBP and pain intensity of ≥4 on an 11-point numerical scale (Brief Pain Inventory [BPI] average pain) were treated with either duloxetine 60 mg once-daily (N = 198) or placebo (N = 203) for 12 weeks in a randomized, double-blind trial. The primary efficacy measure was BPI average pain. Other efficacy measures included BPI-Severity and Interference (BPI-S and BPI-I), response rates (either ≥30% or ≥50% BPI average pain reduction at endpoint), Patient's Global Impression of Improvement (PGI-I), Roland Morris Disability Questionnaire (RMDQ). Health outcome measures included Short Form-36, EuroQoL-5D, and Work Productivity Activity Impairment (WPAI). Duloxene's effect on the reduction of rescue analgesic usage was assessed. Safety and tolerability was also assessed. Compared with placebo, duloxetine-treated patients reported a significantly greater reduction in BPI average pain (p≤.001). Similarly, duloxetine-treated patients reported a significantly greater improvement in BPI-S and BPI-I, 50% response rates, PGI-I, EuroQoL-5D, and some SF-36 domains. RMDQ, WPAI, and 30% response rate showed numerical improvement with duloxetine treatment. A significant reduction in the use of ibuprofen (p=.033), a rescue analgesic, was observed in patients treated with duloxetine compared with placebo. Significantly more patients (15.2%) in the duloxetine group discontinued due to adverse events (p=.002) compared with placebo (5.4%). Nausea and dry mouth were the most common treatment-emergent adverse events and reported significantly more in duloxetine-treated patients. The results demonstrated that duloxetine 60 mg once-daily was effective in reducing CLBP compared to placebo. Duloxetine was safe and fairly well tolerated.