Alcohol and drug interactions in injury to the digestive tract

The ingestion of ethanol can modify the absorption of a variety of drugs. Both inhibition and enhancement of initial rates of absorption have been demonstrated. High concentrations of ethanol enhance damage of the gastric mucosa produced by aspirin, leading to increased bleeding. The principal effect of acute ethanol ingestion on drug metabolism is inhibition of microsomal drug metabolism. Other effects are on non-microsomal drug metabolism; they include enhancement of chloral hydrate reduction and sulphadimidine acetylation and inhibition of glucuronidation of various drugs. Chronic ethanol feeding results in induction of microsomal enzymes with consequent increase in drug metabolism by microsomes. In addition, it can result in enhanced formation of hepatotoxic products from metabolism of certain drugs such as paracetamol (acetaminophen) and the activation of procarcinogens. Other effects of the interactions between drugs and ethanol are the result of changes in organ susceptibility, best demonstrated for the central nervous system.