Lignocaine kinetics in cardiac patients and aged subjects

1 The pharmacokinetics following long term intravenous infusion of lignocaine to cardiac patients have been examined. 2 Plasma levels and half-lives of lignocaine and monoethylglycinexylidide (MEGX) showed wide inter-patient variability. 3 Toxicity reactions to therapy were associated with elevated lignocaine and/or MEGX plasma levels. 4 In a separate study the effect of age on the pharmacokinetics of lignocaine was examined using bolus doses (50 mg) of the drug to young and aged subjects. 5 Elderly subjects had significantly longer half-lives for lignocaine compared to younger individuals although no change in plasma clearance occurred. 6 The drug appeared to distribute differently in the aged as reflected by significantly increased apparent volumes of distribution. 7 The 24 h urinary recovery of the major metabolite (total 4-hydroxyxylidine) showed a significant reduction in the elderly when compared to the young. 8 The clinical significance of these studies with respect to lignocaine therapy has been discussed.