Pregabalin Effective for Chronic Neuropathic Pain Associated with Spinal Cord Injury
HONOLULU, HI—Pregabalin is an effective treatment for patients who experience below-level neuropathic pain following a spinal cord injury, according to data presented at the American Pain Society's 31st Annual Scientific Meeting.
Diana D. Cardenas, MD, MHA, from Pfizer, New York, NY, and colleagues conducted 17-week, randomized, double-blind, placebo-controlled trials in 10 countries to assess the efficacy and safety of pregabalin 150–600mg/day for the management of chronic, below-level neuropathic pain in patients with C2-T12 level of spinal cord injury, complete or incomplete. Below-level pain was defined as being continuous for ≥3 months or remitting/relapsing for ≥6 months. Those with at- or above-level pain were included as long as below-level pain was also present.
Each patient completed ≥4 daily pain diary entries during the 7 days prior to randomization, with an average score of ≥4 on an 11-point rating scale. Pain scores were measured using a numerical rating scale of 0=no pain to 10=worst possible pain. The primary endpoint was Duration Adjusted Average Change (DAAC) in pain, a weighted average of change from baseline at endpoint in mean pain scores based on treatment duration.
A total of 220 patients were randomized to receive pregabalin (150–600mg/day; n=112) or placebo (n=107; 1 patient did not receive study treatment). Patients were predominantly male (80.4%) and had a mean age of 46 years. Median treatment duration was 119 days and the average pregabalin dose was 357mg/day.
Patients treated with pregabalin showed an improved DAAC in pain over the full treatment period (difference from placebo= -0.59; P=0.003). Change from baseline in mean pain score was also greater for pregabalin than placebo; difference from placebo was -0.70 (P=0.007) using a modified baseline-observation-carried-forward (mBOCF) approach for missing data; analysis using a strict BOCF approach provided similar results.
The percentage of patients achieving ≥30% reduction in pain from baseline to endpoint was significantly larger for patients receiving pregabalin than placebo (45.7% vs. 31.4%; odds ratio=1.85; P=0.039); for ≥50% responders, odds ratio was 2.24 (P=0.026). Additionally, pregabalin was superior to placebo in weekly sleep interference improvement and Patient Global Impression of Change scores (both P<0.001) at endpoint. Treatment-related adverse event that occurred commonly with pregabalin were somnolence, dizziness, edema, dry mouth, fatigue, and blurred vision.