Taking Medicines
Drugs in the Body
Medicines can enter the body in many different ways. As drugs make their way through the body, many steps happen along the way. Understanding how medicines work in your body can help you learn why it is important to use medicines safely and effectively.
Absorption into the Body
Drugs are absorbed into the body when they travel from their point of entry into the blood. When you take medicines by mouth, they move through the digestive tract to the liver, the place where the body processes chemicals.
When you take medicines in other ways -- getting a shot, using an inhaler, or applying a skin patch, for instance -- the medicine bypasses the liver and enters the bloodstream directly or through the skin or lungs.
The bloodstream carries medicines throughout the body in a process called distribution. Drugs often interact with many body organs. Side effects can occur if a drug has an effect in an organ other than its target organ.
Drug Metabolism
After a medicine has done its job in the body, the drug is broken down through a process called metabolism. Drug metabolism is the chemical alteration of a medicine by the body.
Often, when a drug is broken down (or chemically altered by the body), it produces products called metabolites. These metabolites are not usually as strong as the original drug, but sometimes they can have effects that are stronger than the original drug.
Because most metabolites are broken down in the liver, scientists refer to the liver as a "detoxifying" organ. As such, the liver can be prone to damage caused by too much medicine in the body.
Exiting the Body
Once the liver is finished working on a medicine, the now-inactive drug enters the excretion stage and exits the body in the urine or feces. Age-related changes in kidney function can have significant effects on how fast a drug is eliminated from the body.
