The effect of a eutectic mixture of local anesthetic cream on wrist pain during transradial coronary procedures

OBJECTIVE: We sought to evaluate the effects and optimal application time of a eutectic mixture of local anesthetic cream (EMLA-C) in relieving wrist pain during transradial coronary procedures (TRCP). METHODS: The Phase I study enrolled 147 patients to evaluate the efficacy and safety of the EMLA-C during TRCP. The Phase II study was designed to evaluate the optimal preprocedure application time frame of EMLA-C for wrist pain reduction in 400 patients. The EMLA or placebo cream was applied at the puncture site from 2 to 4 hours before the procedure in Phase I, and randomized to 5 time groups according to the time of drug application in Phase II. We evaluated wrist pain by the visual analogue scale (VAS) or verbal rating scale (VRS-4), and evaluated complications as well. RESULTS: EMLA-C demonstrated greater pain relief by VAS (control: 49 ± 24, EMLA: 19 ± 22; p = 0.001) and VRS-4 (control: 2.3 ± 0.5, EMLA: 1.5 ± 0.6; p = 0.001), and there was a negative correlation (r = -0.476; p = 0.001) between VAS and the preprocedure application time of EMLA-C. In Phase II, there was a significant difference in pain levels between the control and 1- to 2-hour groups by VAS (control: 49 ± 29, EMLA1-2 hours: 32 ± 24; p = 0.001) and VRS-4 (control: 2.4 ± 0.6, EMLA1-2 hours: 1.9 ± 0.6; p = 0.001). Drug-induced local erythema frequently occurred in the 3- to 4-hour group (6.6%) and > 4 hours group (11.9%). CONCLUSIONS: EMLA-C can be effective in reducing wrist pain during TRCP without any significant drug-related complications when the application time is 1 to 3 hours before the procedure.