Lidocaine patch for acute pain management: a meta-analysis of prospective controlled trials

Background: Local anesthetic is one of the cornerstones of multimodal analgesia. We investigated the efficacy of the lidocaine patch for acute pain management. Methods: We searched MEDLINE, CINAHL, Scopus, and the Cochrane Controlled Trials Register for published prospective controlled clinical trials that evaluated the analgesic effect of the lidocaine patch for acute or postoperative pain management (1966-2014). The outcomes were postoperative opioid consumption, pain intensity and length of hospital stay. Results: Five trials comparing the lidocaine patch with control (no treatment/placebo) for acute or postoperative pain treatment/management were included in this meta-analysis. Data was analyzed on 251 patients. Between the lidocaine patch group and the control group, no significant difference was found for all three outcomes (all p>0.05). For postoperative opioid consumption, mean difference (MD) was -8.2 mg morphine equivalent (95% CI -28.68, 12.24). For postoperative pain intensity, MD was -9.1 mm visual analog scale or equivalent (95% CI -23.31, 5.20). For length of hospital stay, MD was -0.2 days (95% CI -0.80, 0.43). Conclusion: Application of a lidocaine patch may not be an effective adjunct for acute and postoperative pain management, in terms of pain intensity, opioid consumption and length of hospital stay. Limitations: The limitations were a small number of included studies, potential biases from some unblinded studies, clinical heterogeneity between studies, and incomplete reported data for adjunct analgesics.