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Move Over Warfarin (Coumadin®)

Peter J. Zimetbaum, MD

Q & A with Peter J. Zimetbaum, MD

There's a new drug in town for those suffering from atrial fibrillation (AFib), the most common form of abnormal heart rhythm. During atrial fibrillation, the heart's two small upper chambers tremble rather than beat, raising the risk of blood clots and stroke.

Since the 1950s, AFib patients have relied on the anticoagulant warfarin (brand name: Coumadin®) to thin the blood and lower the risk of blood clot developments. Warfarin has proven successful but requires frequent blood draws and monitoring, dosage adjustments and restrictions on eating otherwise healthy foods.

Enter dabigatran (brand name: Pradaxa®), which was approved by the FDA on October 19. In development for nearly 15 years, dabigatran is now available by prescription in pharmacies across the country.

We spoke with Dr. Peter J. Zimetbaum, Director of Clinical Cardiology at BIDMC, about this new drug development and what it means for those living with AFib.

How does warfarin differ from dabigatran?

Dr. Zimetbaum: Both drugs are used to reduce the risk of stroke and blood clots in patients with atrial fibrillation. However, unlike warfarin, dabigatran doesn't require stringent monitoring and, with a recommended dosage of a 150 mg pill twice daily, has a much easier regimen to follow.

Warfarin reduces the liver's ability to make blood clotting proteins from Vitamin K (found in leafy greens). Because warfarin's effectiveness depends upon the amount of Vitamin K in the body and is affected by certain foods and/or medications, patients who rely on it need to monitor their blood closely and change their dosage accordingly.

This is not a concern with dabigatran, which works by reducing the presence of thrombin, an enzyme that coagulates the blood and can lead to clots.

What about side effects? Are they less severe because dabigatran works differently?

Dr. Zimetbaum: Even though warfarin and dabigatran work differently in the body, the side effects remain the same for all anticoagulants. Internal bleeding is the most serious of possible side effects. Other symptoms include stomach discomfort or pain, nausea, heartburn and bloating.

If the side effects are the same for both, what's the incentive to switch to dabigatran?

Dr. Zimetbaum: Warfarin is effective, but research shows that dabigatran is 60% less likely than warfarin to cause brain bleeds-the kind of bleeding that leads to hemorrhagic stroke. Though the risk for preventing clots from traveling from heart to brain-which causes embolic stroke-is about the same for both drugs, the decreased risk of hemorrhagic strokes coupled with the ease of taking the drug gives it an edge over warfarin.

Will dabigatran be covered by insurance?

Dr. Zimetbaum: This is an important question since dabigatran would cost about $6.75 per day without insurance coverage. Currently dabigatran is covered by Harvard Pilgrim insurance with a co-pay. It appears that other health insurance companies are considering providing coverage for the use of dabigatran. Check with your health care insurance provider for more information.

Is dabigatran the only new drug on the market to treat AFib?

Dr. Zimetbaum: There are other AFib drugs on the horizon. Rivaroxaban (brand name: Xarelto®) has emerged as another possible warfarin alternative. Researchers presented their findings on November 15 at the American Heart Association's annual meeting in Chicago. They have found it to be similar to dabigatran in comparison to warfarin-just as effective at preventing embolic stroke but with a lower risk of hemorrhagic strokes. Like dabigatran, Rivaroxaban does not interfere with diet or other medications like warfarin-though side effects remain the same. Rivaroxaban will be presented to the FDA for approval in the future.

What is the significance of these new developments?

Dr. Zimetbaum: This is the beginning of a new generation of medications for those suffering from atrial fibrillation. These drugs will certainly make life easier for many patients who now have the option to treat AFib with a medication that's easy to take.

Above content provided by Beth Israel Deaconess Medical Center. For advice about your medical care, consult your doctor.

Posted December 2010

Contact Information

CardioVascular Institute at
Beth Israel Deaconess Medical Center
330 Brookline Avenue
Boston, MA 02215