Adverse Effects of Medicine

People who take medications, whether for a short period or to treat an ongoing condition, are at risk of adverse effects from the medications they take. An adverse effect, or drug reaction, is any abnormal experience that follows taking the medication. These abnormal experiences can range from mildly uncomfortable to life-threatening, and in some cases they may be fatal. Examples of adverse effects (also called adverse events) include dizziness, rashes and difficulty breathing.

Causes

Adverse reactions to medicine can happen for several reasons. They can be dose-related, allergies, or reasons that are unclear. Medications can interact with each other and cause a problem.
Dose-related adverse effects happen because the person took too much of the medicine, or the body is not clearing the medicine fast enough. For example, a medicine that the liver breaks down may not break down at a normal rate in a person with a bad liver.
In children under 5, according to the Centers for Disease Control and Prevention, dose-related adverse effects happen most often because the child found a medicine container and ate (or drank) the medicine.
Allergic reactions to medicines happen when the body's immune system attacks the medicine or the cell the medicine attaches to.
Some adverse effects of medicines happen for no obvious reason, that there is no immune reaction to the medicine, and the effect is not related to dose.

Symptoms

Symptoms of adverse drug reactions can appear immediately after the first dose or during the course of taking the medication. Not all drug reactions are obvious. For example, if an older patient takes a medication for several weeks and is confused, people may mistake the confusion for part of the aging process and not realize it may be a drug reaction.
Symptoms of adverse drug reactions include anemia (low number of red blood cells), difficulty breathing, dizziness, itching, kidney problems, skin rashes and sun sensitivity.

Treatment

Some drug reaction treatments are mild or easily handled. For example, antibiotics that may cause sun sensitivity are not much of a problem for people who spend most of their time indoors.
Other treatments may involve stopping the drug or reducing the dose. But a person experiencing an adverse reaction may need hospitalization until the reaction is under control. Special medications may be needed to help control a reaction or its aftermath.

Medication Safety

An overdose of medication can cause organ damage or life-threatening situations such as liver failure, kidney failure and difficulty breathing. It is important to remember that over-the-counter medications sometimes have the same active drug as prescription medicine. Check with your doctor or pharmacist that your prescribed medicine and anything you buy off the shelf do not contain the same drug.
Medications can sometimes cause bad effects if they interact with each other. This interaction can cause some medicines to not work, or be less effective. However, the effects of such interactions can also tax the organs that break down and clear the medicines from the body.
Many people don't realize that even herbal supplements affect the body and can cause adverse events on their own or by interacting with other medicines. To reduce the risk of adverse events, make sure your doctor and pharmacist know about everything you are taking, including herbal supplements.

Other Considerations

Be a responsible consumer:
Know what your medications are for, and their possible side effects
Be able to list all the medications you take, including over-the-counter medicine and herbal supplements
Store your medications in their original containers at the right temperature
Do not use medications past their expiration dates
If you or your child accidentally took too much medicine, call the Poison Control Center at 1(800) 222-1222.

Resources

• Medicine Safety: Who's At Risk and What You Can Do