Medication Interactions: Food, Supplements and Other Drugs

Updated:Oct 15,2014

Daily MedicationSome foods — even healthy ones — can make your medications less effective.

Healthy eating is critical for patients battling cardiovascular disease, also called heart disease. In fact, it can help reverse a condition or reduce the need for medication. But even healthy foods, including fruits and vegetables, can cause unintended and possibly dangerous interactions with certain medications.

Perhaps the best-known example is grapefruit, which, along with pomegranate, can alter the way certain cholesterol medications work.

Other examples include some leafy green veggies, such as spinach or kale. Their high vitamin K levels pose risks for patients being treated with blood thinners to prevent strokes. Eating high levels of these  vegetables can counteract the medication’s effectiveness.

Balancing Food and Medication
Winston H. Gandy Jr., a cardiologist with Piedmont Heart Institute in Atlanta and an American Heart Association volunteer, said these potential dangers don’t mean patients get a free pass when it comes to eating their veggies.

It comes down to maintaining a careful balance when using anti-coagulants such as Coumadin (also known generically as warfarin and marketed under the brand names Marevan, Lawarin, Waran and Warfant).

“Coumadin is adjusted to your diet,” Dr. Gandy said. “If you’re eating salad three times a week, then you need to continue that to maintain consistency and balance.”

Interactions from Supplements and Other Medications
Dr. Gandy said food isn’t the only thing to be cautious of when taking blood thinners, also called anticoagulants. Vitamin supplements can also disrupt a carefully balanced dosage of medication. Antibiotics and common pain relievers also can cause the blood to thicken.

On the flip side, some over-the-counter medications used to treat cold and allergy symptoms can cause the blood thinners to have more potent effects.

Other Risks
In the case of statin-based cholesterol medications, including those marketed under brands such as Lipitor, Mevacor and Zocor, grapefruit and pomegranate can be a dangerous mix. Fortunately, Dr. Gandy said, patients who want to keep eating these fruits can be treated with alternative medications.

Other consumables, such as alcohol, can also have an impact on medications due to the way it can change the liver’s ability to filter medication from the body. And even simple things like salt, which is widespread in the food supply can take a toll because it increases the amount of fluid retained in the body, rendering the medication dose inadequate.

“It’s just the way the body processes nutrients and elements,” Dr. Gandy said. “Foods and drugs are just different elements with different purposes, but it’s all handled by the same process. If you overwhelm the system in one way, then it can be affected it in other ways.”

Keep Your Doctors and Pharmacists in the Loop
The key for cardiovascular disease patients is to be aware of the risks and maintain regular communication with healthcare providers, Dr. Gandy said.

“Let your doctor know about any diet formulations you’re on, including any medications or supplements,” he said. When picking up prescriptions or over-the-counter medication, check with the pharmacist to make sure there aren’t any negative interactions. Maintaining a healthy eating pattern  and eating the right amounts for your activity level is also important, Dr. Gandy said.  He encourages patients to be extra cautious around the holidays or during other celebrations when eating habits tend to change.

Common Medication Interactions

Food and drinks don’t mix with certain drugs. They can cause delayed, decreased or enhanced absorption of a medication.

MAO inhibitors and blood pressure: Eating chocolate and peanut butter can be a tasty combination, but eating chocolate and taking certain drugs could carry risks. In fact, eating chocolate and taking MAO inhibitors such as Nardil (phenelzine) or Parnate (tranylcypromine) for depression could be dangerous.

Other blood-pressure raising foods to avoid: aged cheese, sausage, bologna, pepperoni and salami.

Grapefruit: Grapefruit and grapefruit juice can interfere with some prescription drugs, and even a few non-prescription drugs. Don’t drink grapefruit juice with certain blood pressure-lowering drugs because it can cause higher levels of those medicines in your body, making side effects more likely.

Licorice: It probably seems like a harmless snack, but if you’re taking Lanoxin (digoxin) for congestive heart failure and abnormal heart rhythms, some forms of licorice could increase your risk of Lanoxin toxicity. Licorice may also reduce the effects of blood pressure drugs or diuretic (urine-producing) drugs, including Hydrodiuril (hydrochlorothiazide) and Aldactone (spironolactone).

If you’re taking any sort of medication, avoid alcohol, which can increase or decrease its effect.

Learn more:

Also in this section:

Subscribe to Heart Insight magazine and monthly e-newsletter
Heart Insight logo
Our digital magazine delivers helpful articles and the latest news on keeping your heart healthy. Sign up today!



By clicking submit below you agree to the Terms and Conditions and Privacy Policy

Script Your Future

Script Your Future Widget Image
If you don’t take your meds, you’re putting your health and future at risk. Learn about tools that can help with Script Your Future.