Controlled-release oxycodone for pain in diabetic neuropathy - A randomized controlled trial

Background and objective: Opioid treatment has played a limited role in the management of diabetic neuropathy, in part because of concerns about the responsiveness of neuropathic pain to opioid treatment. This controlled study evaluated the efficacy and safety of controlled-release (CR) oxycodone, in subjects with moderate to severe pain due to diabetic neuropathy. Methods: This multicenter, randomized, double-blind, placebo-controlled, parallel-group study included 159 subjects with moderate to severe pain due to diabetic neuropathy. Treatment began with either one 10-mg tablet of CR oxycodone (n = 82) or identical placebo (n = 77) every 12 hours. Doses could be increased every 3 days to a maximum of 6 tablets (60 mg CR oxycodone) every 12 hours. Treatment lasted up to 6 weeks. The primary efficacy variable was overall average daily pain intensity during study days 28 to 42. Results: At an average (SD) dose of 37 (21) mg per day (range 10 to 99 mg/d), CR oxycodone provided more analgesia than placebo (p = 0.002) in the intent-to-treat cohort. From days 28 to 42, overall average daily pain intensity (least squares mean SE), rated in subject diaries on a numeric scale of 0 (no pain) to 10 (pain as bad as you can imagine), was 4.1 +/- 0.3 in subjects given CR oxycodone and 5.3 +/- 0.3 in placebo-treated subjects. Overall, 80 (96%) of 82 subjects given CR oxycodone and 52 (68%) of 77 subjects who received placebo reported adverse events. The most common adverse events in the CR oxycodone group were opioid related. Conclusions: In this 6-week trial, CR oxycodone was effective for the treatment of moderate to severe pain due to diabetic neuropathy. Adverse events were typical of opioid-related side effects.