Blood Thinner Bleeding Risks May Be Worsened By Dosing Problems

Inaccurate blood thinner dosing may be increasing the risk of severe and potentially deadly bleeding events, according to the findings of a new study, which raise questions about claims made by the makers of Pradaxa, Xarelto and Eliquis that users of their new-generation anticoagulants do not require regular medical monitoring.

Researchers with the Mayo Clinic published a study in the June issue of the Journal of the American College of Cardiology, which found that as many as 43% of patients with atrial fibrillation and kidney problems taking drugs belonging to a class of medications known as non-vitamin antagonist oral anticoagulants (NOACs), including Xarelto, Pradaxa, and Eliquis, may be receiving a higher dose than necessary, increasing their risk of bleeding.

The study took data from a large U.S. administrative database, involving 14,865 patients who took one of the three drugs between October 1, 2010 and September 30, 2015. Researchers looked at standard doses in patients with a renal indication, signifying reduced kidney function, for potential overdosing.

According to the findings, 43% of patients were potentially overdosed on blood thinners, which more than doubled the risk of major bleeding events. There was no increased risk in stroke. About 13.3% of the patients were underdosed on blood thinners, which increased the risk of stroke by almost a factor of five.

“In routine clinical practice, prescribed NOAC doses are often inconsistent with drug labeling,” the researchers determined. “These prescribing patterns may be associated with worse safety with no benefit in effectiveness in patients with severe kidney disease and worse effectiveness with no benefit in safety in apixaban-treated patients with normal or mildly impaired renal function.”

Xarelto (rivaroxoaban), Eliquis (apixaban) and Praxaxa (dabigatran) are novel oral anticoagulants introduced in recent years, which have been marketed as superior alternatives to warfarin, which has been the go-to anticoagulation treatment to prevent blood clots for decades.

While the drugs have been aggressively promoted as easier to use, claiming that they do not require the same close monitoring to maintain appropriate dose, concerns have emerged about the safety of the medications, as thousands of reports suggest that users may experience severe and uncontrollable bleeding problems, since the drugs did not have an approved reversal agent at the time they were introduced.

Unlike warfarin, where the blood thinning effects of the drug can be reversed quickly with vitamin K and fresh frozen plasma if bleeding problems develop, no safe and effective antidote was available for Xarelto, Eliquis or Pradaxa when they were introduced.

Due to the drug makers’ failure to warn about the bleeding risk and lack of an effective reversal agent, tens of thousands of Xarelto lawsuits, Pradaxa lawsuits and Eliquis lawsuits have been filed in courts nationwide, each involving similar allegations that the medical community was not adequately warned about the bleeding risks.