Objective: The aim of this study was to determine the efficacy and tolerability of hydromorphone extended release (ER) in patients with chronic low back pain (LBP) with or without a neuropathic component.
Design: This was a post hoc analysis of data from a multicenter, double-blind, placebo-controlled clinical trial using a randomized withdrawal design, performed in patients with moderate to severe chronic LBP. Patients achieving stable doses of hydromorphone ER during a 2- to 4-week conversion and titration phase were randomized to continue treatment with hydromorphone ER or taper-down to placebo during a 12-week double-blind phase. The primary efficacy outcome was the mean change in 11-point Numeric Rating Scale (NRS) pain intensity score from randomization to the final visit of the double-blind phase. Tolerability was assessed by recording adverse events (AEs). Data were analyzed separately for patients with non-neuropathic and neuropathic LBP.
Results: A total of 173 patients with non-neuropathic/nociceptive LBP and 94 with neuropathic LBP were randomized into the double-blind phase. During the conversion and titration phase, mean (SD) NRS scores decreased significantly from 6.5 (1.87) and 6.4 (1.99) at screening to 3.3 (0.98) and 3.2 (1.05), respectively. For both LBP subgroups, patients randomized to hydromorphone ER maintained this improvement over the double-blind treatment period, whereas those randomized to placebo reported significant increase in NRS scores. Across subgroups, the incidence of 1 or more AE was 54 percent to 57 percent in the conversion and titration phase and 47 percent to 55 percent in the double-blind phase.
Conclusions: The results of this study indicate that hydromorphone ER is efficacious and generally well tolerated in the management of patients with non-neuropathic and neuropathic chronic LBP.
Trial registration: ClinicalTrials.gov NCT00549042.