A new study published in the Archives of Internal Medicine indicates that decades-old warfarin is still an equally effective – not to mention less expensive – blood thinner option compared to newer medications, like Pradaxa. Since its 2010 approval by the U.S. Food & Drug Administration (FDA), Pradaxa has been touted as an improvement over warfarin, which has been on the market since the 1950s.
According to a report from MedPageToday, the study, which analyzed data from several randomized controlled trials from the past decade, showed that warfarin carries a low residual stroke risk in patients with non-valvular atrial fibrillation. Pradaxa is indicated to prevent strokes in this same patient population.
“These results could potentially aid the decision process for warfarin therapy for individual physicians and allow health systems to evaluate the cost efficacy of adopting newer agents universally or in specific high-risk clinical subsets,” the study authors wrote.
“Even after consideration of the costs associated with regular INR testing, in most settings, the overall cost of therapeutic strategies using these newer agents will exceed the costs of comparative strategies incorporating generic warfarin,” they said.
In an accompanying editorial, Daniel Singer, MD, of Massachusetts General Hospital in Boston, and Alan Go, MD, of Kaiser Permanente Northern California in Oakland, acknowledged the advantages of the newer anticoagulants over warfarin but also pointed out some risks, MedPage Today said.
Pradaxa is one of those new blood thinners that have been position as a superior alternative to warfarin. Since its October 2010 approval, concerns over serious Pradaxa side effects have grown. Like any blood thinner, both warfarin and Pradaxa pose a risk of serious bleeding. However, warfarin bleeding can be stopped with the administration of vitamin K or a drug called recombinant factor VIIa. There is currently no practical antidote for Pradaxa bleeding.
Last year, Pradaxa’s maker, 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.
In early March, a study in the Journal of Neurosurgery highlighted how dangerous Pradaxa bleeding can be. The report detailed 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.
The case is disturbing because many of the people who take Pradaxa are elderly, and suffer from conditions that could cause them to suffer minor traumas, like falls. The kidneys of older patients may also be less efficient at eliminating Pradaxa, making death from a Pradaxa bleed more likely. In the case of the study patient, his doctors considered trying dialysis to flush Pradaxa from his system, but his condition deteriorated too quickly.
The FDA announced in December 2011 that it had launched a Pradaxa safety review because of reports of fatal bleeding. Weeks after the FDA announced the beginnings of its review, the Institutes for Safe Medicine Practices released reports showing that over 500 cases of Pradaxa-linked bleeding were reported to the FDA during the first quarter of 2011.
