Efficacy of intravenous ketamine for neuropathic pain: a systematic review and meta-analysis of randomized clinical trials.

AIM: This study evaluated the efficacy of intravenous ketamine for chronic neuropathic pain through a systematic review and meta-analysis of randomized clinical trials. METHODS: Searches were conducted in PubMed, Cochrane CENTRAL, and EMBASE until March 2026 in accordance with the PRISMA framework: adult patients with chronic neuropathic pain, intravenous ketamine as the intervention, placebo as the comparator, and pain relief outcomes. RESULTS: Fifteen randomized clinical trials (n = 251) were included in the systematic review, of which six trials (n = 135) were included in the primary outcome meta-analysis. Ketamine doses ranged from 60 µg/kg to 1 mg/kg. Pooled analysis showed that intravenous ketamine was superior to placebo in achieving a ≥50% reduction in pain intensity (RR = 2.79, 95% CI: 1.47-5.30; I2 = 28.3%), with a more pronounced effect in studies using a standardized dose of 400 µg/kg (RR = 5.68; 95% CI: 2.02-15.99; I2 = 0%). However, ketamine was associated with a higher incidence of adverse effects compared to placebo (RR = 3.27; 95% CI: 2.20-4.84; I2 = 20.1%). CONCLUSION: Overall, intravenous ketamine demonstrates the potential to provide effective short-term pain relief. Although adverse events were more frequent, they were generally mild and transient. Methodological heterogeneity and small sample sizes limit the generalizability of these findings.Protocol registration: The www.crd.york.ac.uk/prospero identifier is CRD42021229758.