Pharmacokinetic and Pharmacodynamic Interactions Between Alcohol and Other Drugs

Adverse drug–alcohol interactions represent a major problem in today’s society because of the increasing use of prescription medication in the aging population and the recreational use and abuse of alcoholic beverages throughout adult life. Heavy drinking and drunkenness are major public health problems and ethanol is the drug most frequently encountered in poisoning deaths either alone or together with other substances. Drugs and alcohol can interact in a number of ways, such as by competition for binding sites on hepatic enzymes, which opens the possibility for a metabolic interaction. This is often reflected in a change in the blood or plasma concentration–time curve of alcohol and/or drug and a more rapid or slower rate of elimination from the body (pharmacokinetic interaction). The combined influence of alcohol and other drugs might occur at certain receptor sites or ion channels in the central nervous system and in this way modify behavioral response to drug treatment (pharmacodynamic interaction). This review is concerned with the biological background and the mechanism underlying pharmacokinetic and pharmacodynamic interaction between ethanol and other drugs. Examples are given of ethanol–drug interactions involving common medications (e.g., acetaminophen, benzodiazepines, and other sedatives) as well as drugs of abuse, such as cocaine and GHB.