Safety and pharmacokinetics of EMLA in the treatment of postburn pruritus in pediatric patients: a pilot study.

Abstract

The purpose of this study was to determine the safety and pharmacokinetics of a eutectic mixture of local anesthetics (EMLA) used to ameliorate postburn pruritus after application onto newly formed, intact skin in children. EMLA was applied once to an itchy site where healed skin had formed. Serial blood samples were collected to measure lidocaine, prilocaine, o-toluidine, and methemoglobin. Maximal plasma concentration, minimal plasma concentration, time to achieve the maximal plasma concentration, elimination half-life, and area under the concentration-time curve were calculated. Vital signs, oxygen saturation, clinical signs of hypoxia, and itch intensity were measured. Five children had 15.7 +/- 2.54 g (+/- SD) of EMLA applied to a skin surface area of 93.0 +/- 37.0 cm2. Lidocaine and prilocaine concentrations were below toxic levels; o-toluidine was not detected. Methemoglobin remained between 1 and 3%; patients did not exhibit any clinical signs of hypoxia. Mean oxygen saturation was 98.9 +/- 0.01%. The mean number of pruritic episodes and antihistamine breakthrough doses were greater in the 2 prestudy control days compared with study day 3 (P = 0.01 and P = 0.03, respectively). Skin at the site of EMLA application remained anesthetized for 12 to 13 hours. In this small pilot study, EMLA seems to be a safe, novel treatment for postburn pruritus in burned children when applied to newly healed, intact skin.