First pass effect of gallanilide in rats

The first pass effect of the new anti-arrhythmic compound gallanilide (N-3-diethyla minoethyl)-N-tolyl-3,4,5-trimethoxybenzamide maleate) was compared with that of lidocaine. Intra-femoral or mesenteric vein infusion of gallanilide 5-30 mg/kg at a rate of l mg/(kg-min) elevated the ventricular fibrillation threshold by 3.6-16.4 V or l.6-6.1 V. respectively. While in the case of lidocaine 12.5-75 mg/kg elevated the ventricular fibrillation threshold 3-14.1 and 0.96-4.5 V. respectively. For rats poisoned with carbon tetrachlo-ride or chloramphenicol. the first pass effect of both gallanilide and lidocaine decreased significantly. On the contrary, pretreatment with phenobarbital to induce hepaticmicrosomal enzymes resulted in a considerable increase of the first pass effect of bothdrugs.