Systematic review and meta-analysis of pharmacological therapies for pain associated with postherpetic neuralgia and less common neuropathic conditions

Abstract

To estimate the relative efficacy of pharmacological therapies for the treatment of postherpetic neuralgia (PHN), multiple sclerosis (MS)-related pain, posttraumatic pain, central poststroke pain (CPSP) and human immunodeficiency virus (HIV)-related neuropathic pain (NeP). This systematic review (through June 2011) identified randomised, controlled trials of treatments for these conditions. Bayesian mixed treatment comparison (MTC) methods were used to determine the relative efficacy and safety among the treatments within each pain condition. Fifty studies were identified: 33 PHN, 2 MS-related pain, 3 CPSP, 3 posttraumatic pain and 9 HIV-related NeP. Data from 28 PHN studies including 21 interventions and 4317 patients were included into the PHN MTC. Of treatments studied in ≥ 50 patients, opioids had the greatest mean pain reduction of -1.70 vs. placebo on an 11-point numeric rating scale. Pregabalin ≥ 300 mg/day was most effective for ≥ 30% and ≥ 50% pain reduction [relative risk (RR) vs. placebo = 2.44 and 2.13, respectively]. Data identified for MS-related pain, CPSP, posttraumatic pain and HIV-related NeP were sparse; only 7 of 17 studies had ≥ 50 patients. Adverse events (AEs) and discontinuations for most treatments were not significantly greater than placebo except in PHN, where 8 of 12 treatments had higher risks of AEs compared with placebo and tricyclic antidepressants and opioids had higher risk of discontinuation compared with placebo. Guideline-recommended treatments for PHN were more effective than placebo on the pain NRS and for ≥ 30% and ≥ 50% pain reduction. Although guidelines exist for the management of less common NeP conditions, little published evidence supports them. These results highlight the need for additional evaluations and more complete reporting of outcomes to help guide physicians' treatment selections.