Drug-Food Interactions

Last Updated July 2023 | This article was created by familydoctor.org editorial staff and reviewed by Peter Rippey, MD, CAQSM

A drug-food interaction occurs when your food and medicine interfere with one another. Interactions can happen with both prescription and over-the-counter medicines. These include antacids, vitamins, and iron pills.

Not all medicines are affected by food. Some, though, are affected by what you eat or when you eat it. Taking a medicine at the same time you eat can cause your body not to absorb the medicine. Certain foods may delay or decrease the absorption of the drug. For example, you should not combine dairy and antibiotics. This is why some medicines should be taken on an empty stomach (1 hour before eating or 2 hours after eating).

Some medicines cannot be taken with certain types of food. The food can cause a reaction that changes the effect of the medicine. It also can create or heighten side effects. An example of this is having grapefruit or grapefruit juice with cholesterol drugs. If you take an ACE inhibitor, you should avoid foods high in potassium, such as bananas.

On the other hand, some medicines are easier to handle when taken with food. If you don’t take them with food, you may feel nauseous or dizzy. This is often the case with some antibiotics.

Path to safety

Always talk to your doctor or a pharmacist before taking a new medicine. They can tell you about possible drug-food interactions. Below are more important tips to follow.

  • Read the prescription label on the container. If you don’t understand something, ask your doctor or pharmacist.
  • Read all directions, warnings, and interaction precautions. Even over-the-counter medicines can cause problems.
  • Take all medicine with a full glass of water unless your doctor tells you otherwise.
  • Do not stir medicine into your food or take capsules apart unless your doctor tells you to. This can change the way the drug works.
  • Do not mix medicine into hot drinks. Heat may keep the drug from working.
  • Do not take vitamins at the same time you take other medicine. Vitamins and minerals can cause problems if taken with some drugs.
  • Never take medicine with alcohol.

Things to consider

Taking a new medicine can be hard, especially if there is a risk for interactions. Create a routine for taking one or all of your medicines. Things that may help are:

  • Keeping a calendar for what day and time to take each one
  • Setting an alarm to remind you to take each one
  • Using a pill box to manage your medicines

When to see the doctor

Contact your doctor if:

  • You have any questions about drug-food interactions
  • You have side effects when taking a medicine
  • You don’t feel better or start to feel worse after starting a new medicine

Questions to ask your doctor

  • Is there a certain time of day I should take my medicine?
  • Should I take my medicine with food or on an empty stomach?
  • Do I need to avoid certain foods with my medicine?
  • What happens if I eat certain foods with my medicine?
  • Are there any other substances I need to avoid?


Drugs.com: Drug Interactions Checker

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