Cranberry Juice and Coumadin (Warfarin)

Coumadin is an anticoagulant drug prescribed for patients who are at risk for possible blood clots. Initially, a patient is started off on a low dosage that is gradually increased under a physicians guidance and discretion. The dosage is actually monitored and altered to maintain the correct balance for the duration that the patient uses Coumadin.

Possible Side Effects

coumadin and cranberry juiceMedical reports have reported that at least 12 harmful side effects have been noted when people take Coumadin and cranberry juice together, especially high volumes of cranberry juice such as daily use. One case was even fatal, but the evidence for the cranberry juice and coumadin interaction is not yet conclusive.

In all of the cases so far there is evidence to show that other factors may be responsible or partly responsible, and the fact that there is only 12 documented cases is still too small a number to draw a solid conclusion from. In these cases, the problem was almost always (except one) a result of the blood thinning too much and leading to internal bleeding and/or ineffective wound healing.

Some of the alternative factors that draw attention away from cranberry juice as the problem include pateints having inaqeuate amounts of vitamin K in the blood as a result of not eating a lot of food, or digestive issues that lead to poor vitamin K absorption. Interactions with other medications that patients were taking are another valid possibility.

A Precaution

Even though the possible negative interations between regular cranberrry juice and coumadin intake is not yet confirmed, there is enough evidence for The Evaluation of Drug Interactions to recommend that cranberry juice intake should be limited during Coumadin intake to ensure patient safety.


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