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Can You Stay in the Sweet Spot for Your Warfarin Dose?

It can be difficult to get the warfarin dose just right all the time. Even people who managed it most of the time sometimes had a dangerous deviation.

Warfarin is a classic anticoagulant that is used to prevent strokes and deep vein blood clots. Doctors know a lot about this old inexpensive drug, but they also know getting the warfarin dose just right can be difficult to manage.

Managing the Warfarin Dose Balancing Act:

Physicians at Duke University Medical Center studied the records of more than 3,700 people on warfarin (JAMA, Aug. 9, 2016). They analyzed the INR (International Normalized Ratio) values, a measurement of how well warfarin is blocking blood clotting.

Just about one-fourth of the patients in this group had at least 80 percent of their INR values within range during the first six months. About one-third of those continued to have at least 80 percent of their INR values in range for the rest of the year. For most of these patients, the target INR range was between 2 and 3.

Staying in Range Is Tricky:

Unfortunately, however, at least 36 percent of them had at least one INR reading that was far out of range during that time. A high reading signals the risk of a dangerous bleeding episode, while a low reading points to the possibility of a disabling clot.

The investigators conclude that warfarin dose stability is difficult to predict. The fact that warfarin interacts easily with many other medications as well as foods and beverages probably contributes to this problem. As a result, people taking warfarin need to be very careful about what they eat and drink as well as supplements and drugs.

What About Other Options?

These researchers are enthusiastic about newer anticoagulants that have fewer interactions with food and do not require (or even accommodate) dosing adjustments. As a consequence, drugs such as apixaban (Eliquis), dabigatran (Pradaxa), edoxaban (Lixiama) or rivaroxaban (Xarelto) may be easier for physicians to use, but it is not yet clear that they are better for patients. They are far more expensive, and not all of them can be easily reversed if the patient starts to bleed excessively.

People faced with the need for an anticoagulant long term should have a serious discussion with the prescribing physician and participate in shared decision making. (This Medscape article has a clear explanation. Those who cannot access Medscape may also appreciate this article in Circulation, Nov. 25, 2014.) Also see Hematology, 2013

Can You Take Curcumin with Warfarin?

Q. I take warfarin every day for A-fib and test my INR weekly to adjust my dosage to stay within suggested guidelines. I also have numerous arthritic “hot spots” for which I take 400 mg of ibuprofen once a day.

Would it be wise to delete the ibuprofen, add curcumin and make any necessary adjustments in my warfarin dose to maintain my INR levels? Because I am a retired pharmacist, my cardiologist has given me some leeway in my diet restrictions because of the warfarin. I’m sure I could find the right balance. Do you agree?

A. We would caution most people not to mix curcumin and warfarin. This anti-inflammatory compound derived from turmeric may increase the anti-coagulant power of warfarin.

Because you are testing your INR every week to determine warfarin effectiveness, the change you suggest might work for you. We also worry about interactions between warfarin and ibuprofen that can result in a dangerous bleeding ulcer. As a pharmacist, you are probably aware that this combination is risky.

You may also be interested in other approaches to easing joint pain that might not interact with warfarin. Nine gin-soaked raisins a day don’t work for everyone, but some find this approach helpful. Best, it should not interfere with warfarin.

Learn More:

You can learn more about unorthodox options to ease joint pain in our eGuide to Alternatives for Arthritis. In addition, we offer more details about foods and drugs that interact with warfarin in our free Guide to Coumadin Interactions.

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About the Author
Terry Graedon, PhD, is a medical anthropologist and co-host of The People’s Pharmacy radio show, co-author of The People’s Pharmacy syndicated newspaper columns and numerous books, and co-founder of The People’s Pharmacy website. Terry taught in the Duke University School of Nursing and was an adjunct assistant professor in the Department of Anthropology. She is a Fellow of the Society of Applied Anthropology. Terry is one of the country's leading authorities on the science behind folk remedies..
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