6 Potentially Dangerous Food-Drug Interactions Pharmacists Should Warn Patients About

MAY 09, 2016
Drug-drug interactions can be extremely dangerous, but many patients aren’t aware that the foods they may consume regularly can significantly affect their drug therapy.
Here are 6 potentially devastating food-drug interactions that pharmacists should warn patients about:
1. Chocolate, red wine, and antidepressants.
Along with many beers, aged cheeses, processed meats, and smoked fish, chocolate and red wine contain an amino acid derivative called tyramine.
Mixing tyramine with monoamine oxidase inhibitors (MAOIs) such as selegiline and phenelzine can cause unsafe spikes in blood pressure. Patients should either avoid foods containing tyramine while taking MAOIs or switch to an alternative depression treatment.
2. Leafy green vegetables and warfarin.
Warfarin exerts its therapeutic anticoagulant effect through the inhibition of vitamin K-dependent coagulation factors. Meanwhile, vitamin K is present in many leafy green vegetables like spinach, kale, collards, and broccoli. As a general rule of thumb, the darker green the leafy vegetable is, the higher its vitamin K content.
When combined with warfarin, leafy green vegetables counteract the drug’s anticoagulant effects and place patients at increased risk of thrombosis. Patients should remain consistent with their dietary intake of vitamin K and have their INR monitored regularly while taking warfarin.
3. Dairy and antibiotics.
Dairy products such as yogurt, milk, cheeses, and ice cream all contain calcium. Although it’s a vital micronutrient, the calcium in dairy products as well as antacids may bind to certain antibiotics such as levofloxacin, ciprofloxacin, doxycycline, and tetracycline, consequently decreasing their absorption.
Patients should be advised to take their antibiotics 1 hour prior to or 2 hours after consumption of calcium-containing foods.

Patrick Wieruszewski, PharmD
Patrick Wieruszewski, PharmD
Patrick M. Wieruszewski, PharmD, is a Critical Care Pharmacist at Mayo Clinic in Rochester, Minnesota. He graduated from the University of Florida in 2016 with subsequent completion of a PGY-1 Pharmacy Residency and PGY-2 Critical Care Residency at Mayo Clinic in Rochester, Minnesota. His interests include pulmonary and critical care medicine, immunocompromised hosts, medical writing, and clinical research.