Plasma cocaine and tetracaine levels following application of topical anesthesia in children.

Abstract

To measure plasma cocaine and tetracaine levels in children after standardized application of a solution of tetracaine 0.5%, epinephrine 0.05%, and cocaine 11.8% (TAC) to lacerations requiring suture repair. Nonrandomized, controlled trial over a five-month period. University hospital emergency department. Stable children less than 16 years of age with uncomplicated lacerations. Blood was obtained at either 15 or 20 minutes (early; 32) or 45 or 60 minutes (late; 45) for measurement of plasma cocaine and tetracaine levels. Analysis for cocaine and tetracaine concentrations was performed using gas chromatography-mass spectroscopy with a limit of detection for both assays of 0.5 ng/mL. Serum cocaine levels were low but measurable at both times in 75% of children. No tetracaine was measurable. Median cocaine levels were 1 ng/mL (range, 0 to 112 ng/mL) for the early group and 2 ng/mL (range, 0 to 274 ng/mL) for the late group (P = NS). Only two children had levels of more than 100 ng/mL. No significant correlation between patient or laceration characteristics and cocaine levels was detected. No significant change in heart rate or blood pressure was detected. Children who required additional local anesthesia had nonfacial lacerations and lower cocaine levels than children with facial lacerations. Application of 3 mL of standard TAC solution for 15 minutes results in low but measurable plasma cocaine levels in 75% of children.