Drugs affect everyone differently. So when you’re prescribed a medication, what factors dictate how it will impact your health?
It’s important to be mindful of these points to ensure that your medication is functioning effectively in your body and not resulting in preventable side effects.
Factor 1: Age
Infants and elderly people are the most susceptible to issues with medications. For both groups, their livers and kidneys function less efficiently than the average adult. As a result, drugs that are broken down by the liver or excreted by the kidneys are especially problematic, since they can build up in the body.
Also, elderly people tend to take more medications — and the more drugs you take the more likely you are to have a problem caused by a drug interaction. Older people may also have more difficultly following instructions for medications, making it less likely that they take them correctly.
Factor 2: Genetics
Genetic differences impact how bodies process medications. There’s actually an entire field devoted to the study of genetic differences in response to drugs –– pharmacogenomics.
Genetics can make some people metabolize drugs more slowly than others. Medications can accumulate in the blood and cause toxicity.
Half of all people in the United States possess a liver enzyme that works slowly to metabolize certain drugs. This can be problematic when taking certain drugs, since these individuals’ bodies may destroy red blood cells and cause hemolytic anemia.
Other people metabolize drugs too quickly and drug levels in the blood are never high enough for their medications to be effective.
For example, one in 20,000 people have a genetic defect that makes muscles overly sensitive to certain inhaled anesthetics. When given these drugs with a muscle relaxant, a life threatening disorder called malignant hyperthermia may develop that causes a very high fever, muscle stiffness and decreased blood pressure.
The field of pharmacogenomics is new and evolving, but tests are being released that can help you understand how your body will respond to certain drugs so that you avoid adverse reactions.
Factor 3: Drug Interactions
The effect a drug has on a person may be different than anticipated because that drug is interacting with:
- Another drug that person is taking
- A food, beverage or supplement
- Another disease
Drug interactions can increase or decrease the activity of one or more drugs, resulting in unwanted side effects or failed treatment. These interactions can also occur with both prescription and nonprescription medications.
There are over one dozen additional factors that impact how a drug will respond in the body, including psychological status status, infection, disease, sunlight, exercise and lactation.
Below is a graphic containing factors that affect drug response: