Pradaxa, a new type of blood thinner approved by U.S. regulators in October 2011, may not be living up to its promise. According to a report from The Cleveland Plain Dealer, at least one study published this year has linked Pradaxa to a higher risk of heart attacks. Meanwhile, concerns are mounting about Pradaxa’s bleeding side effects, which are often irreversible.
Pradaxa is used to prevent strokes in people with atrial fibrillation. It was expected to be adopted as a replacement for warfarin, which can have dangerous interactions with certain foods. According to the Plain Dealer, warfarin also requires frequent blood tests to monitor how well the blood is clotting.
Pradaxa was approved by the U.S. Food & Drug Administration (FDA) based on the results of the RE-LY trial, which showed it was effective in preventing strokes, but also hinted at a possible risk of heart attacks linked to Pradaxa, according to The Plain Dealer. In January, a study published in the Archives of Internal Medicine, which pooled data for six smaller trials, found that patients in the Pradaxa groups had a 33 percent increased chance of having a heart attack. Overall, there were 237 coronary events among the 20,000 combined trial participants taking Pradaxa compared with 83 of 10,514 taking warfarin, the Plain Dealer said.
Another problem with Pradaxa is bleeding, a common side effect of all blood thinners, including warfarin. Warfarin bleeding can be stopped with the administration of vitamin K, but there is no similar antidote or Pradaxa bleeding. Earlier this month, a study in the Journal of Neurosurgery highlighted this risk, detailing the worsening condition, and ultimate death, of an 83-year-old Pradaxa patient following a minor fall. Within two hours of his arrival at the hospital, scans showed extensive progression of brain hemorrhaging. His doctors administered intravenous fluids and a protein called recombinant factor VIIa to stop the bleed, but nothing worked. The man fell into a deep coma, and died shortly after.
That incident was just latest report to raise concerns about Pradaxa bleeding side effects. Last year, Boehringer Ingelheim acknowledged that since March 2008, it had received 260 reports of bleeding-related deaths in patients taking Pradaxa. The FDA launched a review of Pradaxa in December over reports of bleeding-related side effects, while regulators in Europe and Japan have also directed Boehringer Ingelheim to strengthen warnings for the Pradaxa.
“What we’ve seen is that the amount of people having death from hemorrhagic events in the brain is higher than expected,” epidemiologist Adrian Hernandez told the Plain Dealer. “That’s another part that’s being played out now as part of this risk-benefit.”