COMPARATIVE TOPICAL ANESTHESIA OF EMLA AND LIPOSOME-ENCAPSULATED TETRACAINE

Background: The eutectic mixture of local anaesthetics (EMLA) provides effective topical anaesthesia after a minimum of 60 to 90 min applica tion, Since liposome-encapsulated tetracaine (LET) can provide rapid d ermal penetration, the goal of this study was to compare the local ana esthetic effects of EMLA and LET in human volunteers after 60 min appl ication. Methods: After obtaining institutional approval and informed consent, healthy volunteers were recruited in a double blind, crossove r, randomized trial, The study creams (0.5 mi EMLA and 0.5 ml LET 5%) were applied randomly to opposite arms for 60 min, The discomfort of i v catheterization was assessed using a visual analogue pain score (VAS ). Cutaneous side effects of the creams were recorded. Results: Sixty- one subjects were studied. Twenty-one were excluded because of technic al difficulties, Forty subjects completed the study and were included in the data analysis, The mean (+/- SD) VAS was lower for LET than for EMLA (10.9 +/- 9.0 mm vs 22.7 +/- 17.1 mm, P < 0.001). Erythema secon dary to vasodilatation occurred more frequent in the LET group than in the EMLA group (33 vs 3, P < 0.001). One subject with a history of at opy developed a rash at the LET application site. Conclusion: Liposome -encapsulated tetracaine can provide a more effective topical anaesthe sia than EMLA for intravenous catheterization after 60 min application , Clinical evaluations are necessary to determine the efficacy and saf ety of LET in providing topical anaesthesia for various invasive percu taneous procedures in other patient populations.