TAC use and absorption of cocaine in a pediatric emergency department

The topical anesthetic TAC (tetracaine 0.5%, adrenaline 0.05%, cocaine 11.8%) has been reported to be effective in pain control for local procedures. However, it has the potential for cocaine toxicity by absorption through an open wound. A study was undertaken to assess the systemic absorption of cocaine and its metabolites when TAC is used as a local anesthetic. Fifty-one children, 1 to 14 years of age, were enrolled in the study. Plasma for cocaine and/or its metabolite levels was available from 46 children and obtained 20 to 40 minutes after the topical anesthetic was applied. No plasma sample had detectable parent cocaine levels; however, 26 (56.5%) had cocaine metabolite levels. Ecgonine methylester levels were detected in plasma from six children and ranged from 59 to 985 ng/mL. Benzoylecgonine levels were detected in none of 19 specimens not preserved with sodium fluoride, and in 23 of 27 specimens to which sodium fluoride had been added. Benzoylecgonine levels ranged from 40 to more than 600 ng/mL. No clinical sign of cocaine toxicity was observed in any child.