Impairment of hepatic drug metabolism in calcium deficiency

The duration of action of hexobarbital but not that of barbital, a nonmetabolized barbiturate, is prolonged in calcium-deficient rats. This finding led to the investigation of the effects of calcium deprivation on drug metabolism in vitro. Calcium deficiency lowers the rate of metabolism of drugs by both oxidative and reductive pathways in liver microsomes. This impairment of hepatic drug metabolism appears to result from a decrease in the specific activity of the enzymes in the liver microsomes.