Should I Drink Cranberry Juice If I Take Coumadin?

Coumadin, which is also known as warfarin, is an anticoagulant drug. Anticoagulants are sometimes given to patients after surgery to prevent the formation of blood clots. They are also prescribed to patients at high risk for heart attack or stroke to "thin" the blood and lessen the chances of a negative event. Because your blood's ability to clot is reduced when you are on Coumadin, you are more likely to bruise easily and bleed profusely when cut. There are a number of foods that can intensify the effects of anticoagulants, so you must watch your diet carefully while you are taking Coumadin.

Cranberry, Quinine, Papaya and Mango

Cranberry, quinine, papaya and mango all increase the effects of Coumadin and lengthen the time that it takes your blood to form a clot. Avoid eating papaya and mango and avoid consuming quinine, which is found in tonic water. A 2006 study by Li Zhoping and others determined that up to 250 mL -- about 1 cup -- of cranberry juice did not increase clotting time in males, so you may drink small amounts of cranberry juice with caution after consulting with your physician.

Vitmains

Vitamins A, K and E are of special concern while you are taking Coumadin, so be sure to clear any supplements containing these vitamins with your doctor before taking them. Excess amounts of vitamin A put you at risk of bleeding, so be sure to stay below the upper limits, which are 10,000 IU for non-pregnant adults and 8,000 IU for pregnant women over 19 years of age. It is also important for you to keep your intake of vitamin K at a constant level prescribed by your doctor. An increased intake of vitamin K will decrease the effects of the drug and a decreased level of vitamin K will increase the effects of the drug. Vitamin K is especially concentrated in green leafy vegetables like kale, Brussels sprouts, mustard greens, beet greens, broccoli, and asparagus. Keep your daily intake of vitamin E between 30 IU, which is the recommended daily allowance, and 400 IU, which is the tolerable upper limit. Consuming vitamin E in excess of 400 IU daily changes the time that it takes your blood to form a clot.

Supplements

Avoid both coenzyme Q10 and St. John's wort as they counteract the effects of Coumadin. Some patients experience interactions between fish oil supplements and Coumadin as well. Gingko, ginseng, saw palmetto and horse chestnut all affect your blood's coagulation and should be avoided while you are taking Coumadin. As always, you should check with your doctor before changing the dosage of your current prescription medications or taking any supplements, whether they are "herbal," "natural" or vitamin supplements.

Foods that Affect Coagulation

Foods containing garlic, onions and ginger call for caution because they are natural blood thinners. Avoid foods that are heavily seasoned with either ginger or garlic. Don't eat more than 60 g of raw, boiled or fried onions in a single day. Sixty grams is roughly equivalent to ½ cup of onions, which you could easily eat in a single order of onion rings if you were not exercising caution.