Articles, Blog

How the Body Absorbs and Uses Medicine | Merck Manual Consumer Version

December 20, 2019

A drug is a chemical or biological
substance that affects the body and its functions. Drug absorption is when a drug
enters the bloodstream. The level of absorption can affect the speed and the
quantity of the drug at the site of action. This is termed bioavailability. If a
tablet releases the drug quickly, blood levels may become too high, whereas slow release may result in low levels of absorption. Additional factors affecting
absorption and bioavailability include the properties of the drug, and the
physiology of the person such as pH levels in the stomach and its speed of
emptying. Therefore specific formulations are used to release the drug at the
desired speed. Common formulations include: tablets, capsules, suppositories,
transdermal patches, and solutions. Drug metabolism is the process by which the
body breaks down drugs which mainly occurs by means of enzymes located in the liver. Many factors including intake of
specific foods and other drugs can increase or decrease the speed at which
drugs are broken down and thus determine their levels within the blood. A drug may
be broken down to stop it from working. However, there are other drugs that need
to be broken down or modified before they become active. These are known as prodrugs. Some drugs are directly eliminated from the body by the kidneys in urne. For this to happen
the drug must be water soluble. Drugs that are not water-soluble may be
metabolized by the liver or enzymes in the blood into breakdown products that
can be eliminated in urine. Diseases that affect the liver or the kidneys can
cause blood levels of a drug to increase.

No Comments

Leave a Reply