Plasma concentrations and analgesic effect of EMLA (lidocaine/prilocaine) cream for the cleansing of leg ulcers.

Abstract

Plasma concentrations of lidocaine and prilocaine were assessed in 8 patients after the application of 8-10 g EMLA 2% cream for 60 min to leg ulcers measuring 31-80 cm2. Maximum individual plasma concentrations were 205 ng/ml for lidocaine and 79 ng/ml for prilocaine, which is twenty times lower than those associated with toxicity. The analgesic effect of EMLA 2% and 5% cream for the surgical cleansing of leg ulcers was compared in a double-blind, four-period, cross-over study in 10 patients. The ulcer was covered with a thick layer of cream for 30 min before four consecutive debridements 1-4 days apart. While the 2% and 5% creams had similar analgesic effects post-cleansing pain tended to be more frequent with the 2% cream.