Pradaxa Heart Attack Concerns Raised By New Study

Additional concerns have been raised about the potential side effects of Pradaxa, after two new studies suggested a potential link between use of the controversial anticoagulant and a risk of patients suffering a heart attack.

In one study, published in the Journal of the American College of Cardiology, researchers looked at “real world” safety profiles of Pradaxa and warfarin, the older anticoagulation therapy that Pradaxa was designed to replace. While Pradaxa performed well against warfarin in the study, the authors wrote a letter to the journal pointing out that Pradaxa may increase the risk of heart attack by 48% when compared to controls.

A second study involving Pradaxa was recently presented at the 2013 Congress of the International Society on Thrombosis and Haemostatis is Amsterdam, which suggested that side effects of Pradaxa may increase the risk of heart attack by up to 70% when compared to patients given a placebo.

The two unrelated studies contradict prior research that suggested the Boehringer Ingelheim drug reduced the risk of heart attacks, also known as myocardial infarctions (MIs).

The study published in the medical journal was an observational study, which is a less exact method than a randomized trial, but researchers used data from the Randomized Evaluation of Long-Term Anticoagulant Therapy (RE-LY) and data Boehringer Ingelheim gave to the FDA to reach their conclusions. The researchers reported that even when you took data from RE-LY out, the heart attack risk from Pradaxa was still high enough to be statistically significant.

The study presented in Amsterdam, conducted by researchers from Belgium, conducted a meta-analysis of randomized controlled trials (RCTs). They found that out of 23,839 patients given Pradaxa, 292 had heart attacks, or about 1.23%. The study found that the risk appeared to increase with higher doses of Pradaxa. Such findings, known as a dose-specific response, are often considered strong indications, but not proof, that there is a causal link between a drug and a side effect.

“This meta-analysis of RCTs provides robust evidence that [Pradaxa] is associated with a significantly increased risk of MI, especially at high dose,” the Belgium researchers concluded. “Health care professionals and regulators should consider appropriate strategy to prevent such serious adverse drug reactions.”

Pradaxa Safety Concerns

Pradaxa (dabigatran) was the first member of a  new class of anticoagulants, which was introduced in October 2010 as a stroke prevention alternative to warfarin, which is more commonly known as Coumadin.

Boehringer Ingelheim has aggressively promoted Pradaxa as superior to warfarin, because it requires less monitoring. However, a concerning number of reports involving uncontrollable bleeding problems with Pradaxa have surfaced since the medication hit the market.

Unlike warfarin, which has a reversal agent that can be used to stop bleeding problems, Pradaxa has no antidote and doctors are often unable to reverse the blood thinning effects of the medication if a user develops a hemorrhage.

Several hundred Pradaxa lawsuits are currently pending against Boehringer Ingelheim, which were brought by individuals who allege that the drug maker failed to adequately warn about the bleeding risk or the lack of a reversal agent for Pradaxa, which could allow doctors to control bleeding that may develop while the medication is used.