Food & Drug Interactions

By: Nikki Nies

Medications are prescribed for everything from acute illnesses to helping with the healing of chronic diseases.  While the use of medications can become necessary, it’s important to know how and if drugs and food will interact with one another.  A food/drug interaction can occur when one of its components interferes with one of the drugs in the body.

There are 4 steps to drug action for medicines taken orally:

  1. Drug dissolves into useable form in stomach
  2. Drug is absorbed into blood and transported to its site of action
  3. Body responds to drug and drug is able to perform its intended function
  4. Drug is excreted from the body either by the kidneys, liver or both.

iron1Risk factors of a negative drug/food interaction may include nutritional status and/or number of medications taken at one time.  Drug absorption can be altered by food consumption.  Certain foods can block the absorption of drugs and interfere with the drug’s ability to complete its intended task.

While not every drug and food interaction is listed below, the chart provided is a great starting place to better understand what medications you’re taking and what precautions you should be aware of.

  Function Body’s response Interaction with Food
Analgesic (acetaminophen) Relieve pain Can cause stomach irritation; increases risk for liver toxicity Good to take with food; a full stomach lowers the risk of stomach irritation
Anticoagulant (i.e. warfarin) Slows the process of blood clotting Can decrease risk of strokes in patients whose blood tends to clot too easily Those taking anticoagulants should be consistent in the amount of vitamin K; important to avoid eating large amounts of foods high in vitamin K
Antacid/Acid Blocker Neutralize stomach acid; acid blockers reduce stomach acid production Regular use can lead to lower B12 absorption even more Can lead to nutrient deficiencies due to stomach acid’s important in the digestion and/or absorption of nutrients; older people produce less stomach stomach, which can lead to low absorption of B12; supplements may be needed
Anticonvulsant (i.e. Phenytoin, Phenobarbital and primidone) Helps control seizures Can decrease appetite; cause diarrhea Can decrease availability of many nutrients; increase the use of vitamin D in body—meaning less vitamin D is available for important functions (i.e. calcium absorption); some decrease folic acid levels; alcohol use can increase drowsiness
Antibiotic (i.e. tetracycline) Treat bacterial infections Pencillin and erthromycin are most effective when taken on an empty stomach due to being partially destroyed by stomach acid when taken with food Some decrease synthesis of vitamin K by bacteria normally found in intestines
Antifungal (Griseofulvin) Treats fungus Increases drug absorption Take with a high fat meal
Antihistamine (i.e. chlorepheniramine, diphenhydramine) Treat allergies Can cause drowsiness; can increase appetiteàweight gain
Antiinflammatory (Naproxen, ibuprofen) Chronic joint pain, headaches and arthritis Can lead to stomach irritation or ulcers; when taken with food or milk it can decrease GI irritation; alcohol can cause damage or stomach bleeding Should be taken with food; avoid alcohol
Diuretic (spironolactone, furosemide, HCTZ) Causes body to excrete more urine; used to treat high blood pressure and fluid build up Can increase urine losses of minerals such as potassium, magnesium and calcium; limit mineral loss; decreases GI irritation May need to avoid or take mineral supplements; take with food
Laxative (Fibercon, Mitrolan) Increase movement of materials through digestive tract Increase fluid losses; can lead to dehydration Reduces the time for nutrient absorption; excessive use can deplete vitamins and minerals needed for normal bodily function
Blood Pressure Lowering Drugs Help control high blood pressure Can cause problems in controlling blood sugar Can negatively impact minerals such as potassium, calcium and zinc; natural licorice found in some candies can cause salt and water retention, which can increase blood pressure
Cancer Drugs (i.e. methotrexate) Used to treat different types of cancer Can irritate cells lining the mouth, stomach and intestines; can cause nausea, vomiting and/or diarrhea Can impact nutrient status—methotrexate can reduce the availability of folic acid, may require supplementation
Mental Health Drugs Can treat depression, anxiety and other mental health conditions Can alter appetite; can impact weight in a significant matter Avoid alcohol with use as it can intensify drowsiness
Lipid Lowering Drugs (i.e. cholestyramine, lovastatin) Reduce blood cholesterol levels Can reduce the absorption of fat soluable vitamins, B12, folic acid and calcium; may be helpful to take a calcium or multivitamin supplement
MAIO Inhibitors (phenelzine, tranylcypromine) Decrease body’s use of monamines Can raise blood pressure levels Can interact with tyramine rich foods—i.e. aged and fermented foods, fava beans, Chianti wine, pickled herring

**It’s best not to drink grapefruit juice while taking medications as it enhances the absorption of some drugs. Wait at least 2 hrs. in between taking medications and drinking grapefruit juice** 

Have you had a particular experience or interaction when taking specific drugs or medications?  What has helped you?


Click to access HE77600.pdf

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