Another 117 bleeding deaths possibly linked to Pradaxa were reported to the U.S. Food & Drug Administration’s (FDA) Adverse Event Database, according to the Institute for Safe Medicine Practices (ISMP) latest QuarterWatch report. The drug watchdog also found that Pradaxa was associated with a total 856 reports of serious, disabling or fatal injury in the second quarter of 2011. Most of the Pradaxa bleeding reports involved people over the age of 80.
In its previous QuarterWatch report, the ISMP had found that more than 500 cases of serious Pradaxa bleeding had been reported to the FDA in the first quarter of 2011. In its QuarterWatch report for the final quarter of 2010, the ISMP noted that Pradaxa was named in more FDA side effect reports than over 98% of the medications the group monitors. According to that report, within 12 weeks of initial marketing approval, Pradaxa was the suspect drug in 307 reported serious adverse events reported to the FDA. It outpaced most other drugs, including warfarin, the group said.
Pradaxa, approved by the FDA in October 2010, is one of a number of new blood thinners that have been positioned as a superior alternative to warfarin, an anti-coagulant that has been marketed for decades. Both warfarin and Pradaxa pose a risk of serious bleeding, a side effect associated with most blood thinners. 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.
The ISMP has also noted in the past that warfarin patients undergo frequent testing to ensure they are not receiving an excessive dose of that drug. But similar tests for Pradaxa, which was approved at single a dose of 150mg twice a day, were not recommended. The group also noted that the U.S. label for Pradaxa does not recommend regular kidney function tests in Pradaxa patients, except for those with severe renal impairment. According to the ISMP, even mild kidney impairment raises Pradaxa blood levels by 50 percent, while moderate impairment can increase levels by 300 percent.
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.