Move Over Warfarin (Coumadin®): New Drug Liberates AFib Patients
Q & A with Peter J. Zimetbaum, MD
There are two new drugs 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®) and rivaroxaban (Xarelto®), both of which have been approved by the FDA in the last one to two years. In development for nearly 15 years, these new drugs are now available by prescription in pharmacies across the country.
We spoke with Dr. Peter J. Zimetbaum, Director of Clinical Cardiology at Beth Israel Deaconess Medical Center, about this new drug development and what it means for those living with AFib.
Q: How does warfarin differ from dabigatran and rivaroxaban?
Dr. Zimetbaum: Both drugs are used to reduce the risk of stroke and blood clots in patients with atrial fibrillation. However, unlike warfarin, dabigatran and rivaroxaban don't require stringent monitoring and, with a recommended dosage of a 150 mg pill twice daily (dabigatran) or 20 mg a day (rivaroxaban), have 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 (direct thrombin inhibitor) or rivaroxaban (factor Xa inhibitor), which work through alternate ways to think the blood and prevent clots.
Q: 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. Rivaroxaban also poses a risk for bleeding and both rivaroxaban and dabigatran require dose adjustment in patients with kidney disease.
Q: If the side effects are the same for both, what's the incentive to switch to dabigatran or rivaroxaban?
Dr. Zimetbaum: Warfarin is effective, but research shows that both dabigatran and rivaroxaban are significantly 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.
Q: Will dabigatran and rivaroxaban be covered by insurance?
Dr. Zimetbaum: This is an important question since dabigatran would cost about $6.75 per day without insurance coverage. Currently, most insurance companies are covering both agents in a Tier 3 status - with a copayment of $40 to $50 per month. Check with your healthcare insurance provider for more information.
Q: Are dabigatran and rivaroxaban the only new drugs on the market to prevent strokes in AFib?
Dr. Zimetbaum: Apixaban is another exciting new drug which may be a warfarin alternative. Like dabigatran and rivaroxaban, this factor Xa inhibitor reduces the risk of stroke from AF without requiring blood test monitoring. In addition, it appears to have a risk of bleeding which is comparable to, if not lower than, warfarin. Apixaban will be reviewed by the FDA in late March of 2012.
Q: 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 the CardioVascular Institute at Beth Israel Deaconess Medical Center. For advice about your medical care, consult your doctor.
Posted January 2013