Originally published on MPR - Monthly Prescribing Reference.
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Vladimir Skljarevski, MD, of Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Ind., and colleagues randomized 401 adults with non-neuropathic chronic low back pain and a pain intensity of ≥4 on the Brief Pain Inventory (BPI), an 11-point numerical scale, with duloxetine 60 mg/day (n=198) or placebo (n=203). The effect of duloxetine, a serotonin and norepinephrine reuptake inhibitor, on reducing use of rescue analgesics was assessed, as was safety and tolerability.
The primary end point of the 12-week study was efficacy of duloxetine 60 mg once daily compared with placebo on reduction in pain severity as measured by the BPI (24-hour average pain ratings). Also assessed were BPI Severity and BPI Interference, response rates (either ≥30% or ≥50% based on BPI 24-hour average pain rating), Patient's Global Impression of Improvement (PGI-I), and the Roland Morris Disability Questionnaire. Health outcomes measures were Short Form(SF)-36, EuroQoL-5D, Profile of Mood States-Brief Form, and Work Productivity and Activity Impairment. Safety and tolerability were assessed by discontinuations due to adverse events, treatment-emergent adverse events, vital signs, and laboratory tests.
Mean age of the patients was 54.9 years in the duloxetine group (59.6% female) and 53.4 years in the placebo group (63.1% female); all patients were predominantly Caucasian (>95%).
Patients treated with duloxetine reported a significantly greater reduction in BPI average pain compared with placebo at 3, 6, 9, and 12 weeks of treatment (P≤0.001). They also had a significantly greater improvement in BPI Severity and BPI Interference, 50% response rates, PGI-I, EuroQol-5D, and some SF-36 domains. A numerical improvement was also observed with duloxetine for the Roland Morris Disability Questionnaire, the Work Productivity Activity and Impairment, and 30% response rate.
Use of ibuprofen was significantly reduced (P=0.033) in the patients treated with duloxetine (12.6%) compared with those in the placebo group (20.7%). Those receiving duloxetine discontinued due to adverse events at a significantly higher rate, 15.2%, vs placebo, 5.4% (P≤0.01). The most common treatment-emergent adverse events were nausea and headache; nausea was reported by significantly more patients treated with duloxetine than with placebo (P<0.001).
Duloxetine is safe and fairly well tolerated, the investigators concluded during their presentation to those attending the American Pain Society's 29th Annual Scientific Meeting.