LAS VEGAS, NV — Hydromorphone extended-release (ER) demonstrated similar efficacy in treating neuropathic or non-neuropathic chronic low back pain (LBP), as presented at PAINWeek 2012.
Srinivas Nalamachu, MD, from International Clinical Research Institute, Overland Park, KS, and colleagues performed a post-hoc analysis on the safety and efficacy of hydromorphone ER in patients with chronic low back pain of neuropathic or non-neuropathic origin, who participated in a previously published withdrawal study.
Investigators pooled data from a double-blind, randomized withdrawal study where patients (n=267, aged 18–75 years) were initially converted from prior opioid therapy to once-daily hydromorphone ER and titrated to a stable effective dose (12mg–64mg) over 2–4 weeks. Patients successfully achieving a stable dose were randomized to continued treatment with hydromorphone ER or placebo for 12 weeks. Immediate-release hydromorphone 2mg, 4mg, or 8mg were allowed as rescue medication.
The primary outcome measures for this sub-analysis included daily mean change in self-reported 1-point numeric rating scale (NRS) during the conversion and titration phase in each group, as well as during the double-blind phase for those continuing on hydromorphone ER. Secondary outcome measures included scores on the Roland Morris Disability Questionnaire (RMDQ), to evaluate patient function on routine tasks. These outcomes were evaluated separately for patients with non-neuropathic (n=67/173 completed; 38.7%) and neuropathic (n=43/94 completed; 45.7%) LBP (classified using the Quebec Task Force Classification of Spinal Disorders).
Both patient groups showed significant reductions in pain intensity during conversion/titration; baseline mean NRS scores for randomized patients at the start of double-blind treatment were 3.3 and 3.2 for neuropathic and non-neuropathic groups, respectively. Similarly, those treated with hydromorphone ER maintained improvements in pain intensity over the double-blind period vs. placebo as demonstrated by Week 12 mean (SD) NRS scores (non-neuropathic: 3.7 [1.79] for hydromorphone ER and 5.1 [2.13] for placebo, P<0.001; neuropathic pain: 3.8
[1.72] and 4.6 [2.07], respectively, P=0.006).
Likewise, improvements in RMDQ scores were maintained at Week 12 with hydromorphone ER vs. placebo in both patients groups by mean change from baseline (non-neuropathic pain: -0.3 for hydromorphone ER and 1.7 for placebo, P=0.022; neuropathic pain: 1.3 and 3.2, respectively, P=0.027).
Dr. Nalamachu concluded, “Regardless of pain etiology patients receiving hydromorphone ER had better pain control over the double-blind treatment period than patients receiving placebo.”