For patients with the heart rhythm disorder atrial fibrillation, a new anti-clotting drug called Pradaxa (dabigatran) can be used as an alternative to warfarin, About 2 million peoples have atrial fibrillation, in which the heart’s two upper chambers beat erratically, causing uneven and inefficient pumping of blood. As a result, blood can pool and clot in the chambers, raising the risk of stroke or heart attack. Since the 1950s, such patients have been prescribed warfarin, but the drug requires regular testing and dosage adjustments.

The updated guidelines, from American Heart Association and the Heart Rhythm Society, say that Pradaxa can be used to prevent blood clots and stroke in patients with either recurrent episodes of atrial fibrillation that stop after seven days called paroxysmal or ongoing permanent atrial fibrillation, and with risk factors for blood clotting and stroke, provided that they don’t have a prosthetic heart valve, significant heart valve disease, severe kidney failure or advanced liver disease.

An updated guideline said a combination of aspirin and the drug Plavix (clopidogrel) could be used to prevent blood clots and stroke in atrial fibrillation patients who are poor candidates for warfarin.