The influence of methohexital on plasma concentration and pharmacokinetic parameters of lidocaine in rabbits.

Cardiac arrhythmia can be a serious complication during general anaesthesia of patients suffering from cardiac arrhythmias and using antiarrhythmic drugs. The aim of the present experiments was to establish the influence of methohexital on the plasma concentrations and pharmacokinetic parameters of lidocaine in rabbits. Lidocaine was administered to rabbits at a dose of 1.0 mgkg(-1) i.v., and methohexital 1.0 mgkg(-1) i.v. Lidocaine levels were determined by immunofluorescence polarisation method using the ABBOTT reagents. Levels of lidocaine were determined in the plasma at 5, 10, 15, 30, 45, 60, 90 and 120 min after the administration of lidocaine. We concluded that the antiarrhythmic action of lidocaine could be reduced after joint administration with methohexital. There exists a probability of shorter action of the lidocaine in methohexital anaesthesia.