More On Adverse Drug Reactions

In a report today, the Journal of the American Medical Association estimates that 700,000 people a year, especially the elderly, experience adverse drug events that lead to emergency room visits. In patients 65 and older, 1/3 of the drug reactions were caused by three medicines: Coumadin a blood thinner, Insulin and Digoxin, a heart medication.

What is an adverse drug reaction?

Adverse medication reactions include side effects, reactions between two or more medications or herbal supplements, reactions between a food and a medication, overmedication, and addiction.

What causes adverse reactions to prescription medicine?

Side effects. Side effects are predictable but unpleasant reactions to a medication.

Allergies. Some people have severe, sometimes life-threatening reactions to certain medications.

Medication interactions. These occur when two or more prescription or nonprescription medications or herbal supplements mix in a person's body and cause an adverse reaction.

Medication-food interactions. These occur when medications react with food. Some medications work best when taken with food, but others should be taken on an empty stomach. Some medication-food reactions can cause serious symptoms.

Overmedication. Sometimes the full adult dose of a medication is too much for small people and those over age 60.

Addiction. Long-term use of some medications can lead to dependency, and severe reactions may occur if the medications are withdrawn suddenly. Narcotics, tranquilizers, and barbiturates must be taken very carefully to prevent addiction.

What sorts of reactions to people have?

Adverse medication reactions may include the following, according to WebMD:

Indigestion, nausea, and vomiting.

Constipation or diarrhea.

Problems with urination.

Dry mouth.

Headache, dizziness, or ringing in the ears

Blurred or double vision.

Confusion, forgetfulness, disorientation, drowsiness, or depression.

Difficulty sleeping, irritability, or nervousness.

Difficulty breathing.

Rashes or bruising.

Bleeding problems.

Don't assume any symptom is a normal side effect of a medication. Call your health professional or pharmacist any time you suspect that your medications are making you sick, WebMD advises.

Are prescription medicines the only cause of adverse reactions?

No. The American Academy of Family Physicians says that even medicines that don't need a prescription (sometimes called over-the-counter medicines) can cause problems. Vitamins, health food products and herbs (in teas or tablets) may also cause adverse reactions. It's important to tell your doctor and pharmacist if you're using these kinds of products.

To learn more about prescription drugs and your health:

• Click here to take a quiz from CBSNews.com about safe prescription drugs.

• Click here for a list of adverse reactions to prescription drugs from WebMD.

• Click here for WebMD's guidelines for taking prescription and nonprescription medications.