Possible Food & Drug Interactions

The effect various food items and drugs have on each other can determine whether medications do their job effectively and whether your body gets the nutrients it needs.

Listed below are some general suggestions that will help you prevent undesirable food-drug interactions when you are taking medications.

  • Follow your physician’s orders about when to take medications and what food or beverages to avoid.
  • Always read the labels of over-the-counter remedies and the package inserts that come with your prescription drugs.
  • Don’t be afraid to ask how drugs might interact with your favorite foods, especially if you consume large amounts of certain foods or beverages.
  • If you are on a special diet be sure to consult with your physician, pharmacist or dietitian regarding how it may affect the medications you have been prescribed.
  • Ask your physician, pharmacist, dietitian, or nurse if you do not understand these instructions or if you want more information.

A member of the nursing team will indicate the medications you will be taking and explain the precautions. Please note that the following are only POSSIBLE food/drug interactions and it does not imply that these effects happen to everyone. This information does not attempt to cover all possible food/drug interactions, but focuses on some of the most clinically significant possible interactions.

ANTIBIOTICS
Antibiotics are used to treat infections in the body. Whether you take this particular class of drugs with food or not can alter their effectiveness.

Levofloxacin (Levaquin), Ciprofloxacin (Cipro), Tetracycline (Sumycin), Minocycline (Minocin), Doxycycline (Vibramycin)—Take 1 hour before or 2 hours after calcium, magnesium, and iron supplements or milk and dairy products.

Metronidazole (Flagyl)—Do not drink alcohol during, and 72 hours after, therapy. The combination can cause flushing, headache, nausea, vomiting, sweating, and rapid heart rate.


ANTICOAGULANTS
Anticoagulants are medications that keep harmful blood clots from forming. The amount of vitamin K in your diet can change the way warfarin (Coumadin) works for you. If you eat a lot of foods that are high in vitamin K, you can decrease the effect of warfarin.

On the other hand, lowering your vitamin K intake can increase the effect of warfarin. You should try to eat a normal, balanced diet keeping the amount of vitamin K the same everyday. It is important that you check with your healthcare provider before making any major changes to your diet. Tell your healthcare provider if there are sudden or drastic changes in your diet due to illness. In general, leafy green vegetables and certain legumes and vegetable oils contain high amounts of vitamin K. Some foods that are low in vitamin K include roots, bulbs, tubers, the fleshy part of fruits, fruit juices, and other beverages. Cereal grains and other milled products are also low in vitamin K. Eat a normal, balanced diet maintaining a consistent amount of vitamin K. All foods are acceptable; however, avoid drastic changes in dietary habits.

Warfarin (Coumadin)

  • Foods high in vitamin K
  • Over-the-counter vitamin supplements with vitamin K
  • Aspirin and products containing aspirin
  • Alcohol (i.e. changes in amount consumed)

ANTIDEPRESSANTS/MOOD STABILIZERS
These agents are taken to relieve mental depression and psychiatric illnesses.

MAO Inhibitors: Isocarboxazid (Marplan), Phenelzine (Nardil), Tranylcypromine (Parnate)—Avoid foods high in tyramine: beer, ale, wine (especially Chianti Red), vermouth, bean curd, soy beans, broad beans, aged cheeses, smoked/fermented/pickled fish, liver, anchovies, aged meats (sausage, pepperoni, salami); yeast, vitamin supplements, protein extracts, sauerkraut, miso soup, dairy products close to expiration date.

Lithium (Lithobid, Eskalith)—Take with food. Maintain adequate fluid intake. Limit caffeine intake. Consistency of sodium (salt) intake is the key to stable lithium levels.


CARDIOVASCULAR DRUGS
These medications are used to treat high blood pressure and heart failure. This is not a complete list of medications in these classes. This list only represents the more common ones.

Benazepril (Lotensin), Captopril (Capoten), Enalapril (Vasotec), Fosinopril (Monopril), Lisinopril (Zestril, Prinivil), Quinapril (Accupril), Ramipril (Altace), Candesartan (Atacand), Irbesartan (Avapro), Losartan (Cozaar), Valsartan (Diovan)—A low sodium, low calorie diet may be recommended. Avoid salt substitutes containing potassium.


MINERALS

Iron Compounds:
Ferrous sulfate (Feosol), Ferrous gluconate (Fergon), Polysaccharide-iron, complex (Niferex)
—May have better absorption when taken on an empty stomach. May take with food to minimize gastric irritation, if needed. Food may decrease absorption by 50%. Vitamin C taken at the same time may increase absorption and may be beneficial. Do not take with cereals, nuts, seeds, rice, beans, dietary fiber, tea, coffee, dairy products, or eggs. Take calcium, zinc, or copper supplements separately.


MISCELLANEOUS

Levothyroxine (Levoxyl, Synthroid)—Take on empty stomach before breakfast to increase absorption. Take iron supplements separately by 4 hours.

Alendronate (Fosamax), Risedronate (Actonel)—Take first thing in the morning with a full glass (6–8 oz.) of plain water only (not mineral water, coffee, tea, or juice). Take at least 30 minutes before first meal, beverage, or any other medication. Do not lie down for at least 30 minutes after taking. Avoid dairy products within 1–2 hours after dose.

Grapefruit Juice—Eating grapefruit or drinking grapefruit juice increases the absoprtion of the following medications and may increase the risk for adverse effects.

Amlodipine (Norvasc), Felodipine (Plendil), Nifedipine (Procardia, Adalat), Diltiazem (Cardizem, Tiazac), Verapamil (Calan, Isoptin), Carbamazepine (Tegretol), Carvedilol (Coreg), Cyclosporin (Neoral), Lovastatin (Mevacor), Simvastatin (Zocor), Atorvastatin (Lipitor), Amiodarone (Cordarone), Buspirone (Buspar), Triazolam (Halcion), Saquinavir (Invirase)

FOODS HIGH IN SODIUM:
Processed and cured meats (cold cuts, hot dogs, deli meats), canned vegetables, soups and meats, frozen dinners, olives, pickles, meat tenderizers, prepared sauces, MSG, cheese, tomato juice

FOODS HIGH IN POTASSIUM:
Most fruits and vegetables (potatoes, yams, tomatoes, winter squash, avocado, dried fruit, oranges, bananas, melons)

FOODS HIGH IN VITAMIN C:
Oranges, strawberries, grapefruit, red peppers, tomatoes, raw cabbage

FOODS HIGH IN VITAMIN K:
Vegetable oils, asparagus, broccoli, brussel sprouts, cabbage, collard greens, kale, lettuce, parsley, peas, spinach, turnip greens, watercress, pickles

FOODS HIGH IN FOLIC ACID:
Dark green leafy vegetables, oranges, legumes, asparagus, broccoli, liver, whole grain cereals, nuts, corn

FOODS HIGH IN TYRAMINE:
Soy Sauce, sauerkraut, chocolate, coffee, raisins, cheese, bananas

FOODS RICH IN CALCIUM:
Milk, cheese, tofu

This information has been prepared for you by Lutheran Health Network Pharmacy Services. It contains information about common interactions that may occur between foods and drugs. It does not attempt to discuss all possible food-drug interactions, nor does it list possible drug-drug interactions. For information regarding drug-drug interactions or the use of alcohol, you should consult your pharmacist or physician. If you have additional questions regarding the information in the pamphlet contact your physician, pharmacist, dietitian, or nurse.

References: Drug: Facts and Comparisons; Micromedex Drugdex® System; Food Medication Interaction; Manual of Clinical Dietics; PharmaCis™; Clinical Integration System for Drug Utilization Review™, Redbook Database Services.

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