This multicenter, randomized, double-blind, placebo- and active-controlled trial was conducted to compare the analgesic efficacy and safety of oxymorphone extended release (ER) with placebo and oxycodone controlled release (CR) in ambulatory patients with moderate to severe chronic low back pain requiring opioid therapy. Patients (N = 213) aged 18 to 75 years were randomized to receive oxymorphone ER (10 to 110 mg) or oxycodone CR (20 to 220 mg) every 12 hours during a 7- to 14-day dose-titration phase. Patients achieving effective analgesia at a stable opioid dose entered an 18-day double-blind treatment phase and either continued opioid therapy or received placebo. With stable dosing throughout the treatment phase, oxymorphone ER (79.4 mg/day) and oxycodone CR (155 mg/day) were superior to placebo for change from baseline in pain intensity as measured on a visual analog scale; the LS mean differences were -18.21 and 18.55 (95% CI, -25.83 to -10.58 and -26.12 to -10.98, respectively; P = .0001). Use of rescue medication was 20 mg per day. Adverse events for the active drugs were similar; the most frequent were constipation and sedation. Oxymorphone ER and oxycodone CR were generally safe and effective for controlling low back pain. Oxymorphone ER was equianalgesic to oxycodone CR at half the milligram daily dosage, with comparable safety.
Perspective: Definitive studies of long-acting opioids in patients with chronic low back pain are lacking. We report the results of a multicenter, randomized, placebo-controlled, double-blind study evaluating the analgesic efficacy and safety of oxymorphone ER and oxycodone CR in opioid-experienced patients with chronic low back pain.