Analgesic Efficacy of a Novel Traditional Chinese Medicine Ointment Against Mechanical Allodynia in Rat Models.

Abstract

<h4>Background</h4>Effective management of procedure-related pain, such as venipuncture, is a critical clinical need. The Eutectic Mixture of Local Anesthetics (EMLA) cream is a standard topical analgesic but has limitations including contraindications and potential adverse effects. The Cortex Erythrinae formula recorded in the Golden Mirror of Medicine is traditionally used to dispel wind-dampness, unblock collaterals, and relieve arthralgia.<h4>Objective</h4>This study aimed to develop a novel Traditional Chinese Medicine (TCM) ointment based on classical prescriptions and to evaluate its efficacy against mechanical allodynia, using EMLA cream as a positive control.<h4>Methods</h4>Fifty male Sprague-Dawley rats were randomly allocated to five groups (n=10). Mechanical allodynia was induced; the mechanical withdrawal threshold (MWT), pain-related behaviors, skin irritation, and systemic toxicity were assessed following topical application of low-, medium-, or high-concentration TCM ointment, EMLA cream, or blank vehicle.<h4>Results</h4>High-concentration TCM ointment significantly elevated MWT (<i>P</i> < 0.001 vs EMLA) and reduced paw-licking and writhing responses, without inducing skin irritation or systemic toxicity.<h4>Conclusion</h4>The high-concentration TCM ointment provided rapid (within 20 min), superior, and cost-effective analgesia with an excellent safety profile, suggesting its promise as an alternative to EMLA for managing mechanical allodynia.