6 Factors That Influence the Risk of Experiencing Medication Side Effects


Medication side effects range from common to rare. While some people may not experience any side effects from a certain medication, others may experience several side effects of the drug. For some individuals, side effects may be mild, whereas for others, they may be severe.

Six factors that influence the risk of experiencing medication side effects include the following:

  1. Age
    Age is the number one influential factor of the risk of experiencing medication side effects. Children and the elderly are the most likely age groups to experience medication side effects. Children tend to process drugs at different rates than adults, making them more susceptible to side effects. The elderly are more likely to be on more medications, which increases the risk of side effects. They also have a reduced ability to metabolize and eliminate medications from the body, which also increases the risk of side effects.
  2. Drug dosage and administration method
    In general, high dosages of drugs are more likely to cause side effects than low dosages. The method of administration (oral, inhalation, injection, etc.) of a drug can also affect the risk of side effects. For example, oral steroids may cause more side effects than inhaled steroids because oral steroids affect the whole body, whereas inhaled steroids specifically target the lungs.
  3. Gender
    Because of the physiological differences between males and females, such as body composition and the speed at which drugs are processed in the body, females are more at risk of experiencing certain medication side effects than men.
  4. Genetics
    An individual’s genes influence how their body reacts to medications. For example, Cytochrome P450-2D6, also known as CYP-2D6, is a liver/intestinal enzyme that works to metabolize medications and other drugs. Variations in the gene that produces CYP-2D6 affect the metabolism of certain medications. The rate at which a drug is metabolized can increase or decrease the risk of side effects.
  5. Lifestyle
    Lifestyle choices affect the risk of experiencing medication side effects. Drinking alcohol increases the likelihood of side effects of many medications. The use of tobacco products affects the metabolism of drugs in the body, which can increase the chance of side effects. Diet and hydration can also affect the risk of medication side effects.
  6. Kidney and liver function
    Some drugs are metabolized in the liver and removed from the body through the kidneys. Individuals who have reduced kidney or liver function may experience more side effects from these types of medications.

Individuals should ask their doctor or pharmacist about how to reduce the risk of medication side effects. For example, taking medication with food may prevent an upset stomach. Drug labels or stickers typically include information about how a medication should be taken and what side effects may occur.