When patients want to lower their chances of developing potentially fatal blood clots, there are now three options for patients with atrial fibrillation (also called A-fib). Coumadin (also called warfarin) is an older drug that has stood the test of time. But newer, more expensive and frequently advertised drugs are very popular. Are Pradaxa and Xarelto better or worse choices for most patients?
Coumadin, Pradaxa and Xarelto are all blood thinners. Atrial fibrillation causes the two upper chambers of the heart to contract too quickly and irregularly. This causes blood to pool, making it more likely for blood clots to form. These drugs are called anticoagulants, and each is prescribed to prevent blood clots and reduce the risk of strokes.
Uses: Coumadin is approved to treat atrial fibrillation, venous thrombosis, pulmonary embolism and to help prevent heart attacks and strokes.  Pradaxa and Xarelto are both approved to treat atrial fibrillation, deep vein thrombosis, pulmonary embolism, and to help prevent strokes. , Unlike Coumadin, Pradaxa and Xarelto are not proven to prevent heart attacks, although doctors hope that they do.
Risks: All blood thinners can cause internal bleeding, which can be deadly. Bleeding to death can be caused by a relatively minor fall or being hit – actions that would normally barely cause any inconvenience. But such bleeding can usually be stopped for patients taking either Coumadin or Pradaxa, if they get to the hospital quickly.
A new drug, Praxbind, was approved by the FDA in 2015 to prevent patients from bleeding to death from Pradaxa after a fall or accident. A study by the company reported that Praxbind prevented excessive bleeding within 30 minutes in 89% of patients.  Most of the patients had side effects, however, some of them serious. These included delirium, constipation, potentially dangerous blood clots, and pulmonary embolism.  There were only 123 patients in the study, which is considered small, and there were very few people of color. For that reason, we don’t know if Praxbind is effective for all patients taking Pradaxa.
In contrast, there is no way to save the life of a Xarelto patient who has started to bleed uncontrollably. That is why Xarelto patients are discouraged from physical activities that could result in falling or internal bleeding.
In addition, both Pradaxa and Xarelto can cause serious spinal cord complications, which can even cause permanent paralysis. Both medications can also cause inflammation of the blood vessels (called vasculitis), which can be minor or can cause serious problems such as blood clots, blindness, and organ damage. 
Cost: Both Pradaxa and Xarelto cost just under $6,000 per year. Coumadin is available as a generic and costs $200 per year. Patients taking Coumadin must also have their blood clotting monitored, to reduce their risk of bleeding. If they go to the doctor, it costs anywhere from about $290 to $950 per year. Patients can also self-monitor their blood clotting time at home using a small drop of blood from a simple finger stick. Self-monitoring costs around $360 per year.  Even with monitoring costs, Coumadin is still much less expensive than Pradaxa and Xarelto. Medicare reimburses Coumadin in full, including monitoring and requires patients to pay part of the cost for Pradaxa and Xarelto.
Convenience: So why would anyone take Xarelto or Pradaxa? The main advantage is convenience. Coumadin patients are required to get their blood monitored frequently to make sure the dose of Coumadin is safe. Although Pradaxa and Xarelto patients would probably also benefit from monitoring, it is not required and for that reason it is not paid for by insurance or Medicare, and not easily available.
Different doses help protect patients: In the U.S., Pradaxa is available in two doses, taken twice a day: 75 mg and 150 mg. The 75 mg dose is prescribed for patients with kidney problems and is less effective in preventing strokes than the higher dose. In other countries, a 110 mg dose is also available and appears to offer a lower bleeding risk while still being effective. Experts have asked why the FDA did not approve the 110 mg dose for sale in the U.S., since it has the potential to be safer for some than the 150 mg dose.  Unfortunately, there is no clear answer to that question.
Xarelto is prescribed in three doses that are usually taken once a day: 10 mg, 15 mg and 20 mg.
Coumadin is available in several different doses which allow doctors to prescribe the dose best suited for each patient.
Here’s a simple chart to compare the 3 drugs. The bottom line: Coumadin is the safest choice, as long as a patient is able to go in for a simple blood test on a regular basis. Isn’t it worth the inconvenience to avoid paralysis or bleeding to death?
|Prevents clotting for those with atrial fibrillation||Yes||Yes||Yes|
|Reliable way to save the patient if drug causes patient to bleed to death||Yes||No||Yes|
|Dietary Restrictions (Must monitor vitamin K intake)||No||No||Yes|
|Requires routine blood monitoring/testing||No||No||Yes|
|Risk of permanent paralysis||Yes||Yes||No|
|Vasculitis (Inflammation of the blood vessels)||Yes||Yes||No|
|Approved for pulmonary embolism, deep vein thrombosis and venous thrombosis||No||Yes||Yes|
All articles are reviewed and approved by Dr. Diana Zuckerman and other senior staff.
- (2016) Coumadin prescribing information. Retrieved from http://www.accessdata.fda.gov/drugsatfda_docs/label/2016/009218s116lbl.pdf
- (2015) Pradaxa prescribing information. Retrieved from http://www.accessdata.fda.gov/drugsatfda_docs/label/2015/022512s028lbl.pdf.
- (2016) Xarelto prescribing information. Retrieved from http://www.accessdata.fda.gov/drugsatfda_docs/label/2016/022406s019s020lbl.pdf.
- (2015) Drug Trials Snapshot Praxbind. Retrieved from https://www.fda.gov/drugs/informationondrugs/ucm470762.htm.
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