Pharmacokinetics and metabolism of lidocaine in patients with renal failure.

The kinetics of distribution and elimination of lidocaine and two of its metabolites, monoethylglycinexylidide (MEGX) and glycinexylidide (GX), were studied in 4 uremic patients on chronic hemodialysis. Each patient received a loading dose of 75 mg of lidocaine, followed by a 30 mug/kh/min lidocaine infusion. No toxic side effects from lidocaine were seen during the study. Average values for lidocaine steady-state plasma levels (2.3 mug/ml) clearance (12.3 ml/min/kg), terminal half-life (148 min), and total volume of distribution (1.9 L/kg) were found, and are similar to those values reported for normal subjects MFGX and after lidocaine infusion averaged 1/5-2/3 of the corresponding lidocaine level, as in nonuremic subjects, and plateaued by 6-8 hr. GX levels did not reach plateau by 12 hr and remained relatively unchanged after infusion. It is concluded that lidocaine infusion in uremic patients is safe, with no abnormal cumulation of lidocaine or MEGX. GX levels, however, may increase progressively, even after 12 hr.