chiefly people who consume alcohol.

chiefly people who consume alcohol, whether in moderate or large quantities, also take medications, at least occasionally. As a follow many people ingest alcohol while a medication is not past nor future in their body or vice versa. A large number of medications - the two those available only by prescription and those available from one side of to the other the counter (OTC) - have the potential to interact with alcohol. Those interactions can alter the metabolism or activity of the medication and/or alcohol metabolism, resulting in potentially serious medical concatenations For example, the sedative events of both alcohol and sedative medications can enhance each other (i.e., the forces are additive), thereby seriously impairing a person's ability to drive or operate other emblems of machinery.

in the greatest degree studies assessing alcohol-medication interactions focus forward the effects of chronic heavy drinking. Relatively limited information is available, however, forward medication interactions resulting from moderate alcohol consumption (i.e., the same or two standard drinks(1) through day). Researchers, physicians, and pharmacists must therefore infer potential medication interactions at moderate drinking flats based on observations made with heavy drinkers. In addition, moderate alcohol consumption may directly influence more [i]or[/i] less of the disease states for which medications are taken (see sidebar, pp 52-53 for further discussion of alcohol's influences onward various disease states). This article discusses alcohol absorption, distribution, and metabolism within the body; the sites where potential alcohol-medication interactions can occur; and possible adverse drifts from various alcohol-medication combinations, including OTC or herbal products

ALCOHOL ABSORPTION, DISTRIBUTION, AND METABOLISM

Gastrointestinal Absorption and Metabolism

When alcohol is ingested end the mouth, a small amount is immediately shaken down (i.e., metabolized) in the stomach. chiefly of the remaining alcohol is then absorbed into the bloodstream from the gastrointestinal tract, primarily the stomach and the upper small intestine. Alcohol absorption come to one's minds slowly from the stomach nevertheless rapidly from the upper small intestine. one time absorbed, the alcohol is transported to the liver in consequence of the portal vein. A portion of the ingested alcohol is metabolized during its initial passage by means of the liver; the remainder of the ingested alcohol leaves the liver, take downs the general (i.e., systemic) circulation, and is distributed from head to foot the body's tissues.

Alcohol metabolism (or the metabolism of any other substance) that happens in the gastrointestinal tract and during the substance's initial passage between the walls of the liver is called "first-pass metabolism" [ILLUSTRATION FOR FIGURE 1 OMITTED]. For example, the mucosa lining the stomach contains enzyme that can metabolize alcohol as well as other substances; about of those enzymes, including alcohol dehydrogenase (ADH) and cytochrome P450 are described in more detail in the section "Alcohol Metabolism in the Liver."

The contribution of stomach (i.e., gastric) enzyme to first-pass alcohol metabolism, however, is controversial. Whereas any researchers have proposed that gastric enzyme play a major part in first-pass metabolism (Lim et al. 1993) other investigators consider the liver to be the primary site of first-pass metabolism (Levitt and Levitt 1998) Furthermore, an gender differences appear to exist in the overall length of, and in the contribution of gastric enzyme to first-pass metabolism. For example, the expansion of first-pass metabolism is les in women than in men and a certain number of studies also have found lower gastric ADH activity in women (Thomasson 1995)

First-pass metabolism is readily detectable after consumption of reasonable alcohol doses(2) that leave the stomach slowly (eg because they have been consum with a meal). Thus, subordinate to such conditions of delayed gastric emptying, more alcohol can be metabolized in the stomach or absorbed slowly from the stomach and transported to the liver for first-pass metabolism.

In general, probably single a small fraction (perhaps 10 percent) of ingested alcohol is eliminated from the material part by first-pass metabolism after consumption of depressed doses of alcohol. As alcohol ingestion increases, the amount of alcohol eliminated by way of first-pass metabolism becomes an steady smaller fraction of the total amount of alcohol consum a researchers have suggested, however, that more [i]or[/i] less medications can block first-pass metabolism, resulting in kindred alcohol levels (BALs) that are higher than normal for a given alcohol dose. For example, tribe taking medications that can inhibit ADH activity - as it was as aspirin and certain medications used to treat sore s and heartburn (i.e., [H.sub.2] receptor antagonists, in the same state [i]or[/i] condition as cimetidine [Tagamet[R]], nizatidine [Axid[R]] and ranitidine [Zantac[R]]) - experience reduc first-pass metabolism (Caballaria et al. 1991; Roine et al. 1990) Similarly, medications that accelerate gastric emptying (eg the stomach medications metoclopramide [Reglan[R]] and cisapride [Propulsid[R]] and the antibiotic erythromycin) may abate first-pass metabolism in the stomach.