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.
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.
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 liver as a "detoxifying" organ. As such, the liver can be prone to damage caused by too much medicine in 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.
While everyone needs to be careful when taking a medicine, older adults frequently take more than one medication at a time, and anyone taking several medications at the same time should be extra careful. Also, as the body ages, its ability to absorb foods and drugs changes.
As people age, the body's ability to break down substances can decrease, so that older people may not be able to metabolize drugs as well as they once did. Thus, older people sometimes need smaller doses of medicine per pound of body weight than young or middle-aged adults do.
All medicines have risks as well as benefits. The benefits of medicines are the helpful effects you get when you take them, such as curing infection or relieving pain. The risks are the chances that something unwanted or unexpected will happen when you use medicines. Unwanted or unexpected symptoms or feelings that occur when you take medicine are called side-effects.
Side effects can be relatively minor, such as a headache or a dry mouth. They can also be life-threatening, such as severe bleeding or irrreversible damage to the liver or kidneys.
Stomach upset, including diarrhea or constipation, is a side effect common to many medications. Often, this side effect can. be lessened by taking the drug with meals. Always cbeck with your doctor, nurse, or pharmacist to see if you sbould take a particular medication with food.
