Medication Interactions: Food, Supplements and Other Drugs

Some 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

Drugs with Food and Beverages

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).

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

Drugs with Dietary Supplements

About half of American adults use dietary supplements. It is recommended that for healthy individuals, all the nutrients you need should come from the foods you eat. Here are some interactions to be aware of:

St. John’s Wort (Hypericum perforatum): This herb is an inducer of liver enzymes, which means it can reduce the concentration of medications in the blood. St. John’s Wort can reduce the blood level of medications such as Lanoxin, the cholesterol-lowering drugs Mevacor and Altocor (lovastatin), and the erectile dysfunction drug Viagra (sildenafil).

Vitamin E: Taking Vitamin E with a blood-thinning medication such as Coumadin can increase anti-clotting activity and could increase your risk of bleeding.

Ginseng: This herb can also interfere with the bleeding effects of Coumadin. In addition, ginseng can enhance the bleeding effects of heparin, aspirin and nonsteroidal anti-inflammatory drugs such as ibuprofen, naproxen and ketoprofen. Combining ginseng with MAO inhibitors such as Nardil or Parnate may cause headaches, trouble sleeping, nervousness and hyperactivity.

Drugs with Other Drugs

Drug-drug interactions occur when two or more drugs react with each other, causing an unexpected side effect. For example, mixing a drug you take to help you sleep (a sedative) and a drug you take for allergies (an antihistamine) can slow your reactions and make driving a car or operating machinery dangerous.

Antihistamines: Over-the-counter antihistamines temporarily relieve a runny nose, or reduce sneezing, itching of the nose or throat, and itchy watery eyes. If you are taking sedatives, tranquilizers or a prescription drug for high blood pressure or depression, you should check with a doctor or pharmacist before you start using antihistamines. Antihistamines taken along with blood pressure medication can cause your blood pressure to increase and may also speed up your heart rate.

Bronchodilators: These drugs temporarily relieve shortness of breath, tightness of chest and wheezing due to bronchial asthma. Ask a doctor before use if you have heart disease, high blood pressure, thyroid disease or diabetes.

Cordarone (amiodarone): Patients taking Zocor (Simvastatin) in doses higher than 20 mg while also taking Cordarone run the risk of developing a rare condition of muscle injury called rhabdomyolysis, which can lead to kidney failure or death. Cordarone also can inhibit or reduce the effect of the blood thinner Coumadin (warfarin), so if you’re using Cordarone, you may need to reduce the amount of Coumadin you’re taking.

Nasal decongestants: These drugs can relieve nasal congestion due to a cold, hay fever or other upper respiratory allergies, but you should ask a doctor if you have heart disease, high blood pressure, thyroid disease or diabetes.

Nicotine replacement products: These drugs can help you kick a deadly habit, but ask your doctor or pharmacist before use if you are taking a prescription drug for depression or asthma, or using a prescription non-nicotine stop-smoking drug. Do not use if you continue to smoke, chew tobacco or use snuff or other nicotine-containing products.

Avoid Problems with These Tips

There are lots of things you can do to take prescription or over-the-counter medications safely.

• Always read drug labels carefully and learn about the warnings for all the drugs you take.
• Keep medications in their original containers so you can easily identify them.
• Ask your doctor what you need to avoid when you are prescribed a new medication. Ask about food, beverages, dietary supplements and other drugs.
• Check with your doctor or pharmacist before taking an OTC drug if you are taking any prescription medications.
• Use one pharmacy for all your drug needs.
• Keep all of your health care professionals informed about everything that you take.
• Keep a record of all prescription drugs, OTC drugs, and dietary supplements (including herbs) that you take. Try to keep this list with you at all times, but especially when you go on any medical appointment.

Before taking a drug, ask your doctor or pharmacist these questions:

• Can I take it with other drugs?
• Should I avoid certain foods, beverages or other products?
• What are possible drug interaction signs I should know about?
• How will the drug work in my body?
• Is there more information available about the drug or my condition?