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Foods That Inhibit Your Medications

food and drug interactions

Picture it: You are walking through the aisles of the grocery store, and as you fill your cart a nagging suspicion begins to form at the back of your mind. What DID the pharmacist say about some foods interacting with your prescriptions? Is anything in your cart going to reduce the efficacy of the prescriptions that keep you healthy?

Common food and drug interactions involve grapefruit juice, licorice, leafy green vegetables, foods that contain tyramine and salt substitutes.

The sour sweetness of grapefruit juice may be calling your name, but if you are taking a prescription medication walk over and pick up some orange juice instead. Grapefruit juice interacts with a multitude of medications in a number of different ways. These interactions are specific to grapefruit juice and not all citrus because grapefruit juice contains compounds called furanocoumarins. Furanocoumarins change the way some medications work within the body. The most common interaction is with Statins -- drugs that lower cholesterol -- by increasing the absorption rate. Grapefruit juice also changes the way we metabolize some medications, affecting the therapeutic levels in our blood. Medications for blood pressure, cough suppressants, antihistamines, thyroid, birth control and stomach acid production can all be affected by grapefruit juice.

Black licorice contains the ingredient glycyrrhiza, which increases potassium loss in the body. Potassium loss causes us to retain sodium. If you are taking digoxin for heart failure the loss of potassium increases the effectiveness of digoxin, creating an abnormal heart beat. Glycyrrhiza makes blood pressure medications less effective and it can also break down warfarin, a blood thinner, increasing the possibility of blood clots.

Leafy green vegetables are normally as tasty and healthy as you can get, but blood thinners like warfarin rely on their ability to interfere with vitamin K-dependent clotting factors. Leafy green vegetables and the skin on cucumbers are high in vitamin K and will decrease the efficacy of blood thinners, risking the possibility of a clot. Here’s the good news; you don’t have to give up your greens! The key when taking blood thinners is maintaining a consistent amount of vitamin K consumption, so don’t change a thing. A consistent amount of greens is the right amount of greens.

Tyramine is an amino acid found in aged cheese, smoked meats, lunch meats, hot dogs, draft beer and chocolate. Tyramine in high levels can increase your blood pressure. Some medications interfere with the breakdown of tyramine, for instance drugs that treat the symptoms of Parkinson’s disease and MAOI’s for depression. If you are taking either of these kinds of drugs, foods rich in tyramine can affect their performance.

Salt substitutes are usually made from potassium and are a great way for people avoiding sodium to adhere to their diet. The caveat is that you must be careful with them. If you are taking ACE inhibitors for blood pressure or digoxin for heart failure the medications use potassium to remove excess sodium from the body. A salt substitute increases the amount of potassium in the diet and decreases the effectiveness of digoxin, thereby increasing the possibility of heart failure.

Bottom line: It’s best to discuss your concerns with your doctor or pharmacist and to explore possible food and drug interactions directly through the drug company’s website. Always read the information included in your prescriptions and don’t be afraid to ask questions. Your body will thank you.

Written by: Ariel Baird, Wellness Workdays Dietetic Intern. Learn more about Wellness Workdays and our wellness program offerings by downloading our brochure.

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