OBJECTIVE: The present randomized, double-blinded, crossover study compared the efficacy and safety of a seven-day buprenorphine transdermal system (BTDS) and placebo in patients with low back pain of moderate or greater severity for at least six weeks.METHODS: Prestudy analgesics were discontinued the evening before random assignment to 5 μg/h BTDS or placebo, with acetaminophen 300 mg/codeine 30 mg, one to two tablets every 4 h to 6 h as needed, for rescue analgesia. The dose was titrated to effect weekly, if tolerated, to 10 μg/h and 20 μg/h BTDS. Each treatment phase was four weeks.RESULTS: Fifty-three patients (28 men, 25 women, mean [± SD] age 54.5±12.7 years) were evaluable for efficacy (completed two weeks or more in each phase). Baseline pain was 62.1±15.5 mm (100 mm visual analogue scale) and 2.5±0.6 (five-point ordinal scale). BTDS resulted in lower mean daily pain scores than in the placebo group (37.6±20.7 mm versus 43.6±21.2 mm on a visual analogue scale, P=0.0487; and 1.7±0.6 versus 2.0±0.7 on the ordinal scale, P=0.0358). Most patients titrated to the highest dose of BTDS (59% 20 μg/h, 31% 10 μg/h and 10% 5 μg/h). There were improvements from baseline in pain and disability (Pain Disability Index), Pain and Sleep (visual analogue scale), Quebec Back Pain Disability Scale and Short-Form 36 Health Survey scores for both BTDS and placebo groups, without significant differences between treatments. While there were more opioid-related side effects with BTDS treatment than with placebo, there were no serious adverse events. A total of 82% of patients chose to continue BTDS in a long-term open-label evaluation, in whom improvements in pain intensity, functionality and quality of life were sustained for up to six months without analgesic tolerance.CONCLUSION: BTDS (5 μg/h to 20 μg/h) represents a new treatment option for initial opioid therapy in patients with chronic low back pain.