Pharmacokinetics And Distribution

Ethanol is quickly and rapidly absorbed from the stomach (about 20%) and from the first section of the small intestines (called the duodenum). Thus the onset of action is related in part to how fast it passes through the stomach. Having food in the stomach can slow absorption because the stomach does not empty its contents into the small intestines when it is full. However, drinking on an empty stomach leads to almost instant intoxication because the ethanol not absorbed in the stomach passes directly to the small intestines. Maximal blood levels are achieved about thirty to ninety minutes after ingestion. Ethanol mixes with water quite well, and so once it enters the body it travels to all fluids and tissues, including the placenta in a pregnant woman. After about twenty to thirty minutes for equilibration, blood levels are a good estimate of brain levels. Ethanol freely enters all blood vessels, including those in the small air sacs of the lungs. Once in the lungs, ethanol exchanges freely with the air one breathes, making a breath sample a good estimate of the amount of ethanol in one's body. A breathalyzer device is often used by police officers to detect the presence of ethanol in an individual.

Between 90 and 98 percent of the ethanol dose is metabolized. The amount of ethanol that can be metabolized per unit of time is roughly proportional to the individual's body weight (and probably the weight of the liver). Adults can metabolize about 120 mg/kg/hr which translates to about thirty ml (one ounce) of pure ethanol in about three hours. Women generally achieve higher alcohol blood concentrations than do men, even after the same unit dose of ethanol, because women have a lower percentage of total body water but also because they may have less activity of alcohol-metabolizing enzymes in the wall of the stomach. The enzymes responsible for ethanol and acetaldehyde metabolism—alcohol dehydrogenase and aldehyde dehydrogenase, respectively—are under genetic control. Genetic differences in the activity of these enzymes account for the fact that different racial groups metabolize ethanol and acetaldehyde at different rates. The best-known example is that of certain Asian groups who have a less active variant of the aldehyde dehydrogenase enzyme. When they consume alcohol, they accumulate higher levels of acetaldehyde than do Caucasian males, for example; this causes a characteristic response called ''flushing,'' actually a type of hot flash with reddening of the face and neck. Some experts believe that the relatively low levels of alcoholism in such Asian groups may be linked to this genetically based aversive effect.

Drug Addiction

Drug Addiction

If you're wanting to learn about drug addiction... Then this may be the most important letter you'll ever read You Are Going To Get A In Depth Look At One Of The Most Noteworthy Guides On Drug Addiction There Is Available On The Market Today. It Doesn't Matter If You Are Just For The First Time Looking For Answers On Drug Addiction, This Guide Will Get You On The Right Track.

Get My Free Ebook


Post a comment