Harvard Health Letter

Ask the doctor: Is the alternative to warfarin safe and effective?

Q. My wife's medication to treat atrial fibrillation recently was changed from warfarin to a new drug called Pradaxa. They say that the new medicine does not require regular INR tests and is just as effective. Is that so?

A. Yes, it is so. Before I explain why, let me provide a little background.

In people with atrial fibrillation, the small upper chambers of the heart (the atria) lose that strong beating action that keeps the blood moving. As a result, blood tends to collect in the atria, and when it does, clots are more likely to form. If a blood clot gets pumped out of the heart and lodges in a blood vessel in the brain, it can cause a stroke. Clots that get stuck in blood vessels elsewhere can also cause serious problems. Anticoagulant drugs like warfarin (Coumadin) and dabigatran (Pradaxa) reduce the tendency for blood to clot.

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