Effect of gender on the monoethylglycinexylidide test in healthy subjects and patients with liver cirrhosis

Sex-related differences in the production of the lidocaine metabolite monoethylglyceinexylidide (MEGX) have only been studied in healthy subjects younger than 45 years of age. These studies found significantly lower MEGX levels in women than men. The aim of this study was to investigate the effect of gender on plasma levels of MEGX in healthy subjects and patients with liver cirrhosis 45 years of age and older. Plasma MEGX concentrations were measured in 10 healthy women and 10 women with Child's class A cirrhosis at 15, 30, 45, and 60 minutes after intravenous administration of lidocaine 1 mg/kg(-1). The results were compared with those previously obtained by using an identical procedure in age-matched healthy men and men with cirrhosis. Healthy women exhibited higher MEGX levels than healthy men, whereas no significant differences were observed between men and women with cirrhosis. Differences in the rate of formation of MEGX between healthy and cirrhotic women mere highly significant at all sampling times. In contrast to the findings in women younger than 45 years of age, women older than 45 years of age exhibited no significant sex-related differences in MEGX levels. Because differences in MEGX production between healthy subjects and patients with cirrhosis were previously evaluated almost exclusively in men, the present study is the first to demonstrate that measurement of plasma MEGX level is a sensitive test for liver cirrhosis in women.