Reduce the risk of adverse drug reactions

Drug interactions occur when one drug interacts with another drug you are taking or when your drug interacts with something you eat or drink. Drug interactions can change the way your medicines work in your body, making your medicines less effective or causing unexpected and potentially dangerous side effects.

Your risk of drug interactions increases with the number of medications you take, both prescription and over-the-counter. In addition, the type of medication you take, your age, diet, illness, and overall health can all affect your risk. Compared with younger adults, older adults are at greater risk for drug interactions because a greater proportion of older adults take prescription or over-the-counter medications. Below are three important types of drug interactions.

medicine interactions

A drug-drug interaction occurs when two or more drugs interact. Prescription and over-the-counter medicines, vitamins, and alternative medicines (such as supplements and herbal products) may interact. Some examples of drug-drug interactions include:

  • Combining prescription sedatives with over-the-counter antihistamines to help you sleep can cause daytime sleepiness and make driving or operating machinery dangerous.
  • Combining aspirin with prescription blood thinners such as Plavix (clopidogrel) can cause excessive bleeding.
  • Some over-the-counter antacids can interfere with the absorption of antibiotics in the blood.
  • Certain medicines used to treat fungal infections can cause serious side effects when combined with cholesterol-lowering medicines such as Lipitor (atorvastatin).
  • some herbal supplements such as ginkgowhich can cause bleeding if taken with aspirin.
READ ALSO:  6 Questions to Ask Before Taking Your Prescription

Drug-Food Interactions

Drug-food interactions occur when a drug interacts with something you eat or drink. Some examples of drug-food interactions include:

  • Dairy products such as milk, yogurt, and cheese can interfere with the absorption of antibiotics in the blood.
  • Many prescription medications are affected by grapefruit juice. Grapefruit juice inhibits an enzyme in the gut that normally breaks down certain drugs, allowing more of the drug to enter the bloodstream.
  • Vegetables that contain vitamin K, such as broccoli, kale, and spinach, can reduce the effectiveness of medications used to prevent blood clotting, such as coumarin (warfarin).
  • Mixing alcohol with certain drugs is especially dangerous. Alcohol interacts with most antidepressants and other drugs that affect the brain. This combination can cause fatigue, dizziness, and slow reaction time. Alcohol can increase the risk of stomach bleeding or liver damage when combined with over-the-counter anti-inflammatory drugs and medications used to treat pain and fever. These drugs include aspirin, ibuprofen, and acetaminophen.
READ ALSO:  What is Ayurveda?

drug-condition interaction

Drug-condition interactions can occur when a drug interacts with an existing medical condition. Some examples of drug-condition interactions include:

  • Decongestants, such as pseudoephedrine, found in many cough and cold medicines, increase blood pressure and can be dangerous for people with high blood pressure.
  • Beta-blockers such as Toprol XL (metoprolol) and Tenormin (atenolol), which are used to treat high blood pressure and certain types of heart disease, can worsen the symptoms of asthma and COPD.
  • Diuretics, such as hydrochlorothiazide, can increase blood sugar in people with diabetes.


  • Talk to your primary care provider or pharmacist before starting any new prescription or over-the-counter medicines. Make sure they know about any vitamins or supplements you take.
  • Be sure to read the Patient Information Leaflet that the pharmacy gave you. If you do not get an information sheet, ask your pharmacist for one.
  • Check your drug label for any warnings and look for the “drug interactions” section. Read these warnings carefully.
  • List all prescription and over-the-counter medicines, including medications, vitamins, and supplements.
  • If possible, use one pharmacy for all prescription and over-the-counter medicines. This way, your pharmacist will keep a record of all your prescription drugs and can advise you on drug interactions and side effects.
READ ALSO:  How to find and use government health and medical websites

Find information about drug interactions

The U.S. Food and Drug Administration (FDA) is responsible for monitoring drug interactions and side effects and ensuring that drugs sold in the United States are safe. The FDA website provides useful information on drug safety issues.