Objective: Gabapentin has been used for the management of post-herpetic neuralgia (PHN). However, inconsistent results have been reported. This meta-analysis was performed to assess the efficacy and safety of gabapentin 1800 mg/day in PHN patients by conducting a meta-analysis.

Methods: Electronic databases were searched for relevant randomized controlled trials (RCTs) that compared gabapentin 1800 mg/day to placebo for PHN. The primary outcomes were reduction in 24-h average pain intensity scores, 50% and 30% pain intensity reduction and gabapentin-related side effects. The secondary outcomes were reduction in sleep rating scores and improvement in Patient Global Impression of Change (PGIC) or Clinician Global Impression of Change (CGIC).

Conclusions: Six RCTs were included. Gabapentin 1800 mg/day reduced the 24-h average pain intensity scores [standard mean differences (SMD) -0·50; 95% confidence interval (CI) -0·88, -0·13; I(2)  = 86·3%] and average daily sleep rating scores [weighted mean differences (WMD) -0·71; 95% CI -1·11, -0·32; I(2)  = 0%]. Gabapentin treatment yielded an improvement in pain intensity (risk ratio (RR) 1·88; 95% CI 1·35, 2·29; I(2)  = 64·8%; for 50% reduction and RR 1·43; 95% CI 1·12, 1·83; I(2)  = 0% for 30% reduction, respectively), PGIC (RR 1·49; 95% CI 1·28, 1·74; I(2)  = 0%), and CGIC (RR 1·58; 95% CI 1·29, 1·92; I(2)  = 30·9%). However, gabapentin increased the somnolence (RR 2·03; 95% CI 1·39, 2·98; I(2)  = 2%), dizziness (RR 2·68; 95% CI 1·95, 3·69; I(2)  = 15%), peripheral oedema (RR 9·10; 95% CI 3·23, 25·60; I(2)  = 2%), total adverse effects (RR 1·28; 95% CI 1·16, 1·42; I(2)  = 0%) and withdrawal due to adverse events (RR 1·51; 95% CI 1·06, 2·16; I(2)  = 6%), but these adverse effects were often mild to moderate. Conclusions: Treatment with gabapentin 1800 mg/day yielded a significant reduction in PHN up to 14 weeks. Gabapentin 1800 mg appeared safe in treating PHN for up to 24 weeks.