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No Evidence of Cranberry/Coumadin Interaction

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Q. Recently I had to increase my dose of warfarin by one mg. On the label it said avoid cranberry juice but I've not seen this on previous warfarin prescriptions. I have atrial fibrillation and that is why I take the anticoagulant.

A. Warfarin (Coumadin) is a blood thinner that prevents blood clots that may lead to a stroke. The dose is critical as too little medicine may permit a blood clot to form while too much could lead to hemorrhaging.

Many foods and drugs interact with warfarin. Several years ago there was a warning that cranberry juice might be among them. Anecdotal reports suggested that cranberry juice might increase the effectiveness of warfarin and cause bleeding.

A review in the American Journal of Medicine (May, 2010) analyzed data from randomized clinical trials and concluded that cranberry juice does not pose a threat when consumed in moderation. Cranberry capsules or concentrate may be another matter. Periodic monitoring is advised for anyone on warfarin.

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I read in your column that results were not conclusive regarding cranberry juice reaction to warfarin. I am taking warfarin due to an embolism I had last summer. But I also take cranberry juice because of tendency to get cystitis. Your advice was that it could be consumed in "moderation."
Now I need to know what is considered "moderation." Thanks so much for your help.

PEOPLE'S PHARMACY RESPONSE: A GLASS OR TWO A DAY COULD BE CONSIDERED MODERATE; A QUART WOULD NOT.

Afib is curable! I had various arrhythmias that were eliminated (for 3 years so far) by ablation. The procedure is fairly easy with catheters being inserted in your groin. My doctor was Francis Marchlinski at the University of Pennsylvania Hospital. He was one of the early developers of the technique -- especially the procedure to treat problems on the side of the heart not easily reached (pokes a hole through the atrium).

I highly recommend looking into ablation as a cure. There are a couple of approaches (freezing versus radio-wave) that are in use. Marchlinski prefers (as of my procedure) radio-wave, but either are (I think) effective. Cure rates for one procedure run about 90%, I think. A second procedure may be required if the first is not completely successful.

Risks are pretty low. For someone like Marchlinski that does this several times per day, risks are minimal. As in any procedure, get the statistics for the doctor, not just the procedure!

Best,

Joe

What about cranberries or dried cranberries? In the past I used them in salads and in certain rice dishes. I quit eating cranberries in Oct, when I had an episode of A-Fib. I am now on Warfarin. I really miss having cranberries.

PEOPLE'S PHARMACY RESPONSE: ACCORDING TO THIS RESEARCH, IF YOU ARE MODERATE IN YOUR CRANBERRY CONSUMPTION YOU NEED NOT WORRY.

I had a reaction from sulphur about 60 years ago. Would that reaction be in my body today? Thank you,

I would say moderation and consistency. If you consume the same (small) amount of Cranberry juice on daily bases your INR (test for level of anticoagulation) will reflect any interaction that may exist between Cranberry juice and Coumadin and it will be easier to to adjust your Coumadin dose if there is a need.

If you decide to start or stop drinking cranberry juice you should let your doctor know about it so he or she may consider doing the blood test to check you INR more frequently until it normalizes. In any case you should discuss the drinking of cranberry juice with your doctor as the decision about consuming cranberry juice on daily bases may depend on your other medications that you are taking, your medical conditions, how easy it is to adjust your Coumadin dose to reach proper anticoagulation and your personal risks for bleeding.

Marianna

www.healthialist.com

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