Effects of Alcohol-Metabolizing Enzyme Inhibitors and Beta-Lactam Antibiotics on Ethanol Elimination in Rats

The in vivo effects of alcohol-metabolizing enzyme inhibitors and beta-lactam antibiotics upon the ethanol elimination rate were examined in rats. Intravenous administration of ethanol caused a dose-dependent increase in blood ethanol level, and the ethanol elimination could be well described by a two compartment model. Pretreatment of rats with enzyme inhibitors caused a marked decrease in the ethanol elimination rate associated with the depression of the enzyme activities. Fasting of the animals caused a decrease in the ethanol elimination rate per animal associated with a decrease in the liver weight. However, no alteration was evident when the rate was expressed as the rate per g of liver. When animals were pre-treated with a high dose of N-methyltetrazolethiol (NMTT) containing beta-lactam antibiotics or NMTT itself, which causes a disulfiram-like reaction, the ethanol elimination rate per animal was depressed concomitant with an increase in the blood acetaldehyde level. The ethanol elimination rate in these animals showed lower values even when expressed as the rate per g liver. On the other hand, administration of cephems without NMTT, which cause no disulfiram-like reaction, led to a slight decline in the elimination rate per animal, although no alteration was detected when the rate was expressed as the rate per g liver. The findings indicated that the ethanol elimination in vivo per animal is regulated by the total capacity of the alcohol-metabolizing enzyme activities in the whole liver.