Bleeding Risk with Pradaxa Higher Than Warfarin: Study

The findings of new research suggests that individuals using the novel anticoagulant Pradaxa may be more likely to suffer bleeding problems than users of the drug warfarin, adding to the recent concerns surrounding potential side effects of new-generation blood thinners, which also include Xarelto and Eliquis. 

In a study published in the January issue of the medical journal JAMA Internal Medicine, researchers from the U.S. and Spain found that the side effects of Pradaxa were linked to over a 50% increased risk of a major bleeding events, and an 85% increased risk of gastrointestinal bleeding when compared to it’s older competitor.

Pradaxa (dabigatran) was the first member of a new class of anticoagulants introduced in the United States, approved in late 2010 for prevention of strokes among patients with atrial fibrillation. The medication quickly became a blockbuster drug, and has been followed by the introduction of Xarelto and Eliquis, in 2011 and 2012 respectively.

All of the novel anticoagulants have been promoted as superior alternatives to warfarin, which has been the go-to blood thinner for prevention of strokes among atrial fibrillation patients for decades. Amid aggressive marketing that suggest the drugs are easier to use and just as effective, combined sales of the new-generation drugs have grown to more than $2 billion a year. However, concerns have emerged about the risk of severe bleeding problems with Pradaxa, Xarelto and Eliquis.

While all blood thinners carry a risk of bleeding, as the medications are designed to prevent clotting, which can make bleeds difficult to control, the effects of warfarin can be quickly reversed with the use of vitamin K and fresh frozen plasma in the event. However, there is no similar antidote currently available for Pradaxa, Xarelto or Eliquis, causing many doctors to report incidents of severe and uncontrollable bleeding among users of the newer drugs..

In the latest study, researchers from the University of Pittsburgh and La Paz University Hospital in Madrid, Spain, looked at pharmacy and medical claims from 2010 to 2011, involving newly diagnosed patients with atrial fibrillation. They found data on 1,302 Pradaxa users and 8,102 warfarin users.

The findings indicate that Pradaxa was associated with a 30% higher overall bleeding rate than warfarin. Specifically, the risk of major bleeding was 58% higher, and the risk of gastrointestinal bleeding was 85% higher. However, Pradaxa was linked to fewer incidents of intracranial bleeding, with only a third the risk of brain bleeds when compared to warfarin.

“Dabigatran was associated with a higher incidence of major bleeding (regardless of the anatomical site), a higher risk of gastrointestinal bleeding, but a lower risk of intracranial hemorrhage,” the researchers concluded. “Thus, dabigatran should be prescribed with caution, especially among high-risk patients.”

New Blood Thinner Bleeding Risks

When Pradaxa was first released it quickly became associated with a high number of adverse event reports to the FDA and hundreds of bleeding deaths in the U.S. alone.

More than 4,000 Pradaxa lawsuits were ultimately filed against Boehringer Ingelheim, alleging that the drug maker failed to adequately research the medication and withheld proper warnings about the bleeding risk and lack of a reversal agent.

Following several years of litigation, the drug maker agreed to pay $650 million in Pradaxa settlements earlier this year, with an average of about $150,000 paid to resolve claims brought on behalf of former users who experienced injuries from uncontrollable bleeds.

As concerns about the safety of Pradaxa mounted, Xarelto has grown to become the most widely used of the new-generation blood thinners. However, similar reports of Xarelto bleeding problems have surfaced, with users experiencing uncontrollable gastrointestinal hemorrhaging and death.

Bayer Healthcare and Johnson & Johnson’s Janssen subsidiary now face a growing number of Xarelto lawsuits, which raise similar allegations to those presented in the Pradaxa litigation.

Many of the claims indicate that the drug makers failed to adequately explore all potential reversal agents, suggesting that Xarelto should be removed from the market until a safe and effective antidote for bleeding problems is identified.