Comparative topical anesthesia of liposome-encapsulated tetracaine (LET) and emla

Our previous study has shown that LET provided better topical anesthesia compared to an eutectic mixture of local anesthetics (EMLA) after 1 hr application. We conducted another randomized, double-blind study to further investigate the topical anesthetic effect of LET and EMLA for intravenous catheter (IV) placement following 30 minute application in 24 healthy volunteers. The study creams were randomly applied to opposite forearms for 30 minutes. An #18 IV catheter was then inserted in each site. The discomfort was assessed using a visual analogue pain score (VAS). The data were analyzed using paired t-test and Wilcoxon signed-rank test where appropriate. There were no differences in the duration of cream application, and the time for IV insertion. The VAS was significantly lower for LET compared to EMLA (36.9±23.5 mm vs 26.0±17.8 mm, p<0.05). These findings suggest that LET provides more effective topical anaesthesia compared to EMLA for IV placement following a 30 minute application. This rapid onset of topical anesthesia of LET may prove to be a more convenient and appropriate preparation for invasive procedures in the future.