The effect of oral omeprazole on the disposition of lignocaine

The effects of the gastric antisecretory drug, omeprazole, on the disposition of lignocaine were studied in 10 healthy male volunteers in a double-blind, randomised, placebo-controlled, two-period crossover trial. Omeprazole 40 mg or placebo was taken daily for one week before administration of lignocaine 1 mg.kg-1 (3.7 mumol.kg-1) given intravenously over 10 min. Venous concentrations of lignocaine and its metabolite monoethylglycinexylidine were measured in plasma with reversed phase liquid chromatography. The mean (95% CI) areas under the curve at infinity for lignocaine after pretreatment with omeprazole or placebo were 6.67 (4.90-8.45) mumol.h.l-1 and 6.14 (5.05-7.23) mumol.h.l-1, respectively (p = 0.44). The respective areas for monoethylglycinexylidine were 1.85 (1.25-2.45) mumol.h.l-1 and 1.79 (1.44-2.14) mumol.h.l-1 (p = 0.78). Similarly, omeprazole had no significant effect on the half-lives of lignocaine or methylglycinexylidine.