Controlled-release oxycodone and naloxone in the treatment of chronic low back pain: a placebo-controlled, randomized study.

Abstract

For Canadian regulatory purposes, an analgesic study was required to complement previously completed, pivotal studies on bowel effects and analgesia associated with controlled-release (CR) oxycodone⁄CR naloxone. To compare the analgesic efficacy and safety of CR oxycodone⁄CR naloxone versus placebo in patients with chronic low back pain. Patients requiring opioid therapy underwent a two- to seven-day opioid washout before being randomly assigned to receive either 10 mg⁄5 mg CR oxycodone⁄CR naloxone or placebo every 12 h, titrated weekly according to efficacy and tolerability to 20 mg⁄10 mg, 30 mg⁄15 mg or 40 mg⁄20 mg every 12 h. After four weeks, patients crossed over to the alternative treatment for an additional four weeks. Acetaminophen⁄codeine (300 mg⁄30 mg every 4 h to 6 h as needed) was provided as rescue medication. Of the 83 randomized patients, 54 (65%) comprised the per-protocol population. According to per-protocol analysis, CR oxycodone⁄CR naloxone resulted in significantly lower mean (± SD)pain scores measured on a visual analogue scale (48.6 ± 23.1 mm versus 55.9 ± 25.4 mm; P=0.0296) and five-point ordinal pain intensity scores (2.1 ± 0.8 versus 2.4 ± 0.9; P=0.0415) compared with placebo. After the double-blinded phase, patients and investigators both preferred CR oxycodone⁄CR naloxone over placebo. These outcomes continued in the 79% of patients who chose to continue receiving CR oxycodone⁄CR naloxone in a six-month, open-label evaluation. In patients complying with treatment as per protocol, CR oxycodone⁄CR naloxone was effective for the management of chronic low back pain of moderate or severe intensity.