Methaemoglobin formation after the use of EMLA cream in term neonates

Abstract

EMLA cream 5% (a eutectic mixture of lidocaine and prilocaine) is a topical anaesthetic that has become widely used to minimize pain from venipuncture in children. It has not, however, been recommended in neonates owing to the potential risk of methaemoglobinaemia induced by prilocaine. The aim of this study was to establish the safety of 1 g EMLA cream 5% used on intact skin in term neonates. Forty-seven neonates, aged 0-3 months, with a postconceptual age of > or = 37 weeks and a body weight between 2.8 and 5.7 kg, were included in a double-blind, randomized, placebo-controlled study. After baseline observations a total dose of 1.0 g EMLA/placebo was applied to two sites (0.5 g site(-1)) for 60-70 min. Venous methaemoglobin (metHb) levels were determined in each patient at baseline and at three randomly assigned times, 0.5-18 h after application. Following application of the cream, the mean metHb levels were 1.17% (range 0.50-2.53) in the EMLA group and 0.96% (range 0.50-1.53) in the placebo group. The metHb concentrations were significantly higher in the EMLA group in the intervals from 3.5 to 13 h after application than in the placebo group, but were well below potentially harmful levels. Based on these results, a 1-h application of 1 g EMLA cream is safe when used on the intact skin of term neonates below 3 months of age.