Is Pradaxa® better or worse than warfarin?

Pradaxa was introduced to the U.S. in October 2010 to prevent blood clots in people with atrial fibrillation, or irregular heartbeat. It was thought to perform better than anticoagulant warfarin, which has been used since 1954 but requires frequent blood tests and takes a toll on the liver. However, Pradaxa’s drawbacks were revealed within weeks after its release when a number of reports linked the drug to side effects including heart attack, brain hemorrhaging, internal bleeding, gastrointestinal bleeding, and death.

This January, a group of Cleveland Clinic researchers found a 33 percent increased risk for heart attack across seven trials including more than 30,000 patients. But Pradaxa’s maker, Boehringer Ingelheim, is skeptical."We don't agree with the conclusion and the method used for this meta-analysis,” says Dr. John Smith, senior vice president for clinical development and medical affairs at Boehringer Ingelheim. “Based on all the data, we conclude that heart attack is not an adverse consequence of Pradaxa treatment."

Cleveland Clinic’s research team isn’t yet certain. “It's possible Pradaxa doesn't increase heart attack risk directly, but it may not be as effective as warfarin and aspirin in preventing heart attacks,” says Dr. Ken Uchino, director of the Vascular Neurology Fellowship Training Program at the Cleveland Clinic.

A 2009 study showed that Pradaxa is 34 percent better at lowering stroke risk than Warfarin. But Pradaxa’s risk for uncontrolled bleeding is higher. Earlier this month, an 83-year-old man died of severe brain bleeding after a simple fall that can be common among the elderly.

Roughly 2 million people take blood thinning medications every day to prevent dangerous blood clots from forming and causing a heart attack or stroke. Warfarin is the most commonly prescribed anticoagulant, and 31 million prescriptions were written for the drug in 2004.

Dr. Uchino suggests weighing Pradaxa and warfarin’s pros and cons with your doctor. “The risk appears to be there,” Uchino says of Pradaxa, “but the benefit is there, too. I don’t think it’s that straightforward. A lot of things in medicine aren’t straightforward.”