Plasma levels of 2% lidocaine with 1:100,000 epinephrine with young children undergoing dental procedures.

Lidocaine levels were determined for 12 children, aged 55 to 150 mo, who received routine dental treatment, including multiple intraoral injections of 2% lidocaine (2.6 to 6.4 mg/kg) with 1:100,000 epinephrine. Peak plasma concentrations of lidocaine ranged from 0.7 to 3.8 mug/ml at 5 to 15 min postinjection. Generally accepted threshold concentrations for the onset of central nervous system toxicity are 5 to 10 mug/ml. In this study, no child approached these levels when given local anesthesia for dental procedures.