Controlled-release oxycodone relieves neuropathic pain: a randomized controlled trial in painful diabetic neuropathy.
BACKGROUND
Painful neuropathy is one of the most common long-term complications of diabetes mellitus and often proves difficult to relieve.


METHODS
Patients with diabetic neuropathy with moderate or greater pain for at least 3 months, were evaluated for efficacy, safety and health-related quality of life (QOL) while receiving controlled-release (CR) oxycodone (OxyContin) or active placebo. Patients underwent washout from all opioids 2-7 days before randomization to 10 mg CR oxycodone or active placebo (0.25 mg benztropine) q12h. The dose was increased, approximately weekly, to a maximum of 40 mg q12h CR oxycodone or 1 mg q12h benztropine, with crossover to the alternate treatment after a maximum of 4 weeks. Acetaminophen, 325-650 mg q4-6h prn was provided as rescue.


RESULTS
Thirty-six patients were evaluable for efficacy (21 men, 15 women, mean age 63.0+/-9.4 years). CR oxycodone resulted in significantly lower (P=0.0001) mean daily pain (21.8+/-20.7 vs. 48.6+/-26.6 mm VAS), steady pain (23.5+/-23.0 vs. 47.6+/-30.7 mm VAS), brief pain (21.8+/-23.5 vs. 46.7+/-30.8 mm VAS), skin pain (14.3+/-20.4 vs. 43.2+/-31.3 mm VAS), and total pain and disability (16.8+/-15.6 vs. 25.2+/-16.7; P=0.004). Scores from 6 of the 8 SF-36 domains and both summary scales, Standardized Physical Component (P=0.0002) and Standardized Mental Component (P=0.0338) were significantly better during CR oxycodone treatment. The number needed to treat to obtain one patient with at least 50% pain relief is 2.6 and clinical effectiveness scores favoured treatment with CR oxycodone over placebo (P=0.0001).


CONCLUSIONS
CR oxycodone is effective and safe for the management of painful diabetic neuropathy and improves QOL.
D000368:Aged; D000701:Analgesics, Opioid / Q000008:administration & dosage* / Q000009:adverse effects; D018592:Cross-Over Studies; D003692:Delayed-Action Preparations; D003929:Diabetic Neuropathies / Q000188:drug therapy* / Q000503:physiopathology / Q000523:psychology; D004185:Disability Evaluation; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008603:Mental Health; D008875:Middle Aged; D010098:Oxycodone / Q000008:administration & dosage* / Q000009:adverse effects; D010147:Pain Measurement; D010919:Placebos; D012867:Skin / Q000503:physiopathology
D000701:Analgesics, Opioid; D003692:Delayed-Action Preparations; D010919:Placebos; D010098:Oxycodone