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Categories: Diabetes & Nutrition, Nutrition

When Food and Medications Don’t Mix: Preventing Food-Drug Interactions

Kitty Finklea, RD, AFAA-CPT
Registered Dietitian

Did you know certain foods and beverages may change how your medications work? When what you eat or drink affects what the medication is supposed to do, this is called a food-drug interaction. A food-drug interaction may prevent a medicine from working properly, cause a side effect to get worse or better, or even cause a new side effect.

Typical food-drug interactions can cause a variety of symptoms including:

  • Changes in taste or appetite
  • Digestive changes like nausea, vomiting, constipation, diarrhea, pain, bleeding, or bloating.
  • Metabolic changes that may encourage weight gain or loss, higher or lower blood pressure or blood sugar

Certain medications need to be taken with food and other medications need to be taken on an empty stomach for optimal absorption. For example, thyroid medications are typically taken on an empty stomach and antacids work better with or after food.

Common food-drug interactions include alcoholic beverages, increasing drowsiness or inhibiting absorption of certain drugs. Foods high in calcium decrease the absorption of certain antibiotics, making them less effective. Vitamin K foods such as greens can interfere with Coumadin, a blood thinner.

Some food-drug interactions can also be dangerous. For example, when grapefruit juice is consumed with certain cholesterol-lowering, blood pressure, or anti-anxiety drugs, this can make the medicine build up in the body and cause liver or kidney problems. The general rule of thumb is to wait at least 2-4 hours between consuming a food or beverage that may interfere with your medication but confirm with your provider or pharmacist.

With more than 20,000 different medications on the market, and many people taking a handful of medications daily, it can be challenging to keep up with food-drug interactions. Here are guidelines to help keep food-drug interactions from affecting you:

  • Talk to your provider about all your medications and discuss any potential food-drug interactions, particularly with any new medications
  • Make sure to clarify with your provider if a medication should be taken with or without food and what time of day
  • Know why you’re taking a medication even if you can’t pronounce the name
  • Read the medication instructions and insert info given with all new medications to familiarize yourself with any potential side effects or food-drug interactions
  • Review all your medications with your pharmacist anytime you have a change in your medications and ask for any food-drug interactions as well as any drug-drug interactions
  • Keep notes on any potential food, beverage, or supplement that interferes with any medications
  • Pay attention to any changes in your body when first starting a medication and, if needed, discuss with your provider and pharmacist

Take charge of your health – know how your medications work, how they should be taken , what food or beverages might interfere with them , and if you have any questions or concerns, talk to your treatment team and pharmacist, they’ll be happy to help!



HopeHealth educates its patients on the importance of having a health care home. As a primary care facility, HopeHealth’s medical team works to prevent and detect illness and the early onset of disease, provide routine physical examinations and promote overall healthy lifestyles.

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