The results of a recent Pradaxa study show the anticoagulant’s risk of causing bleeding injuries increases if the patient also takes certain statin drugs.

The Pradaxa study was published in the Nov. 21 issue of the Canadian Medical Association Journal.

Researchers tracked the experiences of almost 46,000 patients over age 65 who were taking Pradaxa to reduce the risk of stroke associated with atrial fibrillation.

The researchers specifically tracked the incidence of ischemic stroke and major hemorrhage among these patients.

Of those patients, the ones who also took lovastatin (Mevacor) or simvastatin (Zocor) showed as much as a 40 percent greater risk of major hemorrhage compared to others who took different statins.

According to the author of the Pradaxa study, “[a]n increase in the risk of bleeding requiring hospital admission or emergency department visits was seen with lovastatin and simvastatin compared with the other statins.”

The Pradaxa study also suggests that taking on the increased risk of bleeding doesn’t necessarily improve a patient’s odds of avoiding stroke. The researchers say they found no difference in the risk of ischemic stroke among patients who took different statins along with Pradaxa.

Researchers in the Pradaxa study believe lovastatin and simvastatin both tend to increase the amount of Pradaxa absorbed in the body by blocking the action of a protein that limits how much Pradaxa the body can absorb.

That increase could amplify Pradaxa’s anticoagulant effect, increasing the risk of bleeding injuries already associated with the drug.

Other statins do not block the same protein and so would not have a similar effect on Pradaxa absorption, the researchers say.

Pradaxa Study Examines Interactions with Statins

By one estimate, as many as half the patients taking Pradaxa are also taking a statin.

Statins are a widely-prescribed class of drugs used to reduce blood serum cholesterol. Lower cholesterol levels can reduce the risk of cardiovascular conditions like angina, heart attack or stroke.

Pradaxa, also known by its generic name dabigatran, is a relatively new anticoagulant drug. Anticoagulants are often prescribed to reduce the risk of stroke that comes with atrial fibrillation a condition that affects around 2.7 million persons in the U.S.

Pradaxa is also FDA-approved as a treatment and preventive for other blood clot-related conditions like pulmonary embolism and deep vein thrombosis.

Pradaxa was developed as a competitor for warfarin (Coumadin), which had been medicine’s go-to anticoagulant for decades. Pradaxa was developed so that patients could avoid the dietary restrictions and ongoing blood monitoring required for those who take warfarin.

Pradaxa has already been the subject of thousands of pharmaceutical products liability lawsuits. In 2012, the number of claims grew large enough that the federal Judicial Panel on Multidistrict Litigation established a multidistrict litigation in a federal court in Illinois.

Claimants in Pradaxa lawsuits generally seek to hold its manufacturer Boehringer Ingelheim accountable for bleeding injuries they were allegedly not properly warned about.

The plaintiffs say the company failed to issue a proper warning that would put patients and their physicians on notice about the real risks of bleeding associated with Pradaxa.