Just a year after the Food and Drug Administration (FDA) approved Pradaxa (dabigatran) to prevent blood clots in patients with a life threatening type of irregular heartbeat known as atrial fibrillation, the agency announced it was looking into reports of serious bleeding events associated with the drug. The review was prompted by a European Medicines Agency (EMA) safety update that noted “a worldwide total of 256 spontaneous case reports of serious bleeding resulting in death.”
But serious bleeding was not the only concern the EMA expressed about Pradaxa. A meta-analysis of seven randomized clinical trials published online in the January 2012 Archives of Internal Medicine showed that Pradaxa appeared to increase the risk of heart attack and acute coronary syndrome, compared with a placebo or other blood thinners including warfarin and enoxaparin.
An EMA advisory panel also recommended that the blood thinner be labeled to advise testing for renal function in all patients before starting treatment and, for those taking the drug, renal function assessment at least once a year in patients older than 75 years and in patients of any age with a suspected decline in renal function. Some studies show that moderate renal failure increases the risk of heart attack and death.
Pradaxa is a class of anticoagulants known as direct thrombin inhibitors. They work by directly inhibiting the enzyme thrombin. As of August 2011, less than a year after its approval, more than 250,000 prescriptions had been written for Pradaxa in the United States alone.