High-concentration (8%) capsaicin patch for chronic postoperative neuropathic pain: A systematic review of randomised...

Chronic postoperative neuropathic pain is a common and sometimes disabling problem. Mainstay pharmacological management involves gabapentinoids, tricyclic anti-depressants and serotonin and norepinephrine reuptake inhibitors. Past this, guidance is limited. There is good evidence for the use of high-concentration capsaicin patch in non-operative causes of neuropathic pain. This systematic review aimed to evaluate the evidence base for the high-concentration (8%) capsaicin patch for postoperative neuropathic pain.

We carried out a systematic search of 4 databases (Ovid MEDLINE, Embase, Cochrane Library and https://ClinicalTrials.gov) from inception to 3rd July 2025 to identify randomised controlled trials investigating the effectiveness of high-concentration capsaicin patch for postoperative neuropathic pain. The primary outcome was pain improvement, with adverse events being the secondary outcome. Study selection was performed independently by two reviewers using the Rayyan platform.

487 studies were identified. After screening, only one randomised controlled trial on 46 participants met inclusion criteria. The high-concentration capsaicin patch did not significantly improve postoperative neuropathic pain compared to an inactive placebo patch. However, the certainty of evidence was graded as very low using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. We also found 2 ongoing trials without published results.

This systematic review identified a clear gap in the literature regarding the use of high-concentration capsaicin patches for chronic postoperative neuropathic pain. High-quality studies are needed to expand the existing evidence base. Based on our findings, we propose several recommendations to guide future research in this area.