6 Foods That Can Cause Dangerous Interactions With Common Medications  

Some foods can make certain drugs less effective, or even trigger a potentially dangerous response, so it’s important to ask your healthcare professional or pharmacist if there is a potentially problematic pairing. Here are some examples of foods and beverages that should be avoided when taking certain medications.

Dairy.

According to AARP, antibiotics in the tetracycline family, such as doxycycline and minocycline, that are used to treat bacterial infections, and the drug ciprofloxacin, often prescribed to treat pneumonia, can be affected by the calcium in dairy products. Consuming cheese, milk and yogurt while taking these pills can affect the drug’s absorption. Avoid calcium-containing foods an hour before, or two hours after, taking these medications, says Bethanne Brown, a clinical professor of pharmacy at the University of Cincinnati College of Pharmacy.

Leafy greens.

Leafy greens are rich in vitamin K, which interacts with the blood-thinning drug warfarin (Coumadin). Vitamin K is used by the body to make blood-clotting factors, but warfarin reduces the action of vitamin K, says US News & World Report. Experts say that the risk is decreased if you are consistent in the amount of greens you eat. “The problem comes when somebody eats a spinach salad every day for a few weeks until the bag of spinach runs out, and then goes the next week without eating any,” says Tasha Woodall, associate professor of clinical education at the University of North Carolina Eshelman School of Pharmacy.

Grapefruit.

Eating a grapefruit or drinking grapefruit juice can interact with certain statin drugs, erectile dysfunction drugs, chemotherapies, calcium channel blockers to treat high blood pressure, and some allergy medications. Check with your pharmacist or doctor and avoid drinking large amounts of grapefruit juice if you are on these drugs or drug classes, says Woodall.

Meat and fish.

High-protein foods such as meat and fish may make dopamine drugs less effective. These drugs are used to treat Parkinson’s patients and consist of amino acids, or protein building blocks. Levodopa, the active ingredient in the drug Sinemet, converts to dopamine in the brain. “We tell people to try to avoid taking Sinemet with a really protein-rich food — don’t take it with a steak,” says Woodall. Experts suggest taking the Parkinson’s medication on an empty stomach so that food doesn’t compete with the drug for absorption.

Bananas.

If you are taking an ACE inhibitor to lower blood pressure, avoid eating bananas and other potassium-rich foods, says AARP. These include avocados, tomatoes, and dried apricots, which when combined with this class of drugs can potentially cause dangerous heart arrythmias, says Brown.

Chocolate and pickled, cured, and fermented foods.

According to U.S. News & World Report, aged cheeses, smoked fish, chocolate, wine, beer, and some processed meats contain tyramine, a substance that can negatively interact with certain drugs that treat depression. For example, tyramine slows down the breakdown of monoamine oxidase inhibitors (MAOIs), an older class of antidepressant. This can lead to a harmful rise in blood pressure.