Question

identify the major nonhaptic route of elimination of alcohol and its medicolegal implications

Answer 1

When a person consumes alcohol, the first place that the alcohol goes after it leaves the tract is the liver. Once it enters the capillaries surrounding the stomach and small intestines, the capillaries lead to the portal vein, which enters the liver and branches out once again into capillaries. Ethanol diffuses from the capillaries into the nearby hepatic cells.

Once ethanol is in the circulation, it reaches all tissues in the body, including the brain, where it causes intoxication. Our bodies are designed to terminate the action of drugs, including alcohol, so that the intoxication doesn’t persist when a person stops drinking. In fact, the body starts eliminating ethanol before it even gets into the general circulation. In the hepatic cells or as it is called the liver, some of the ethanol is converted, or detoxified by enzymes to inactive products. This process is called metabolism , and the products are called metabolites.

Firstly, metabolism is a way of turning off the action of a drug. In general, metabolites have less biological activity relative to the parent compound.

Secondly, metabolism helps to convert the drug into a more polar form so it can be carried in the bloodstream to the kidneys, where it is excreted in the urine. During metabolism, the enzymes actually help speed up the reactions, but the speed is different for different people.

The rate of metabolism remains constant during continued drinking. As the consumption of alcohol increases there are not enough molecules in the liver or the stomach to metabolize the extra alcohol efficiently. So, alcohol begins to accumulate in the bloodstream, giving an increased blood alcohol concentration that leads to intoxication.

Now the alcohol which is not metabolized on its first passage through the liver continues to circulate throughout the body as an active drug. Ultimately, only a small fraction of the ingested alcohol escapes metabolism. This small amount of alcohol is eliminated unchanged in the breath as vapor or in the urine. Thus the absorption of alcohol from the gastrointestinal tract, including the stomach, occurs by simple passive diffusion along concentration gradients and does not involve an active transport system.

Elimination of alcohol occurs principally through enzymatic oxidation in the liver, with usually minor nonhepatic oxidation pathways and minor excretion of unaltered alcohol in the urine, breath and perspiration.

Statutory terminology refers to the amount of alcohol in the person’s blood, urine, breath or other body substances. The alcohol distribution process and the partition ratios for alcohol between blood and other specimen material s are of great practical importance.