Pharmacokinetic approach to the clinical use of lidocaine intravenously

The time course of lidocaine plasma concentrations following various modes of administration were predicted by computer. Initiating therapy with a single intravenous bolus dose was unsatisfactory; plasma levels during the first hour were potentially toxic after a 200-mg bolus and subtherapeutic after a 50- to 100-mg bolus. After two bolus doses of 100 mg, separated by 20 to 30 minutes, or a rapid loading infusion over 15 to 60 minutes, therapeutic concentrations were achieved and maintained. Pharmacokinetic principles can be of value in devising rational approaches to lidocaine dosage.