Objective: To summarize the efficacy and examine the safety and tolerability of pregabalin in patients with central neuropathic pain due to spinal cord injury (SCI).
Research design and methods: Data were pooled from two 12 to 16 week, placebo-controlled trials of pregabalin in patients with neuropathic pain due to SCI. Pain diaries were used to rate pain from 0 = no pain to 10 = worst possible pain. Efficacy measures included: mean change in pain from baseline to endpoint; duration adjusted average change (DAAC) in pain; the percentage of patients with ≥30% or ≥50% reductions in pain score from baseline to endpoint; and Patient Global Impression of Change (PGIC) score at endpoint. Adverse events (AEs) were also compared between treatment groups.
Results: In total 174 patients received placebo and 182 received pregabalin. Mean change in pain from baseline to endpoint was improved in the pregabalin group compared with placebo (placebo-adjusted difference = -0.79; 95% CI = -1.15, -0.43; p < 0.001; baseline-observation-carried-forward). DAAC in pain was improved in patients receiving pregabalin compared with placebo (p < 0.001). The percentage of patients achieving ≥30% and ≥50% reductions in pain from baseline to endpoint was greater in the pregabalin arm compared with placebo (placebo: 30% = 22.5%, 50% = 11.6: pregabalin 30% = 35.6%, 50% = 22.4%) (all p < 0.01). PGIC scores at endpoint were significantly better in the pregabalin arm compared with placebo (p < 0.05). Treatment-related AEs, most commonly somnolence, dizziness, dry mouth, fatigue, edema, blurred vision, and constipation occurred more frequently in patients treated with pregabalin than placebo. The majority of AEs were mild to moderate in severity.
Conclusions: Pregabalin reduced neuropathic pain due to SCI over a 12 to 16 week treatment period. Treatment-related AEs were mostly mild to moderate in severity and are consistent with the known safety profile of pregabalin. These findings should not be extrapolated to longer durations of treatment or other patient populations.