Pradaxa Bleeding Problems and Adverse Event Reports

For the second year in a row, the controversial anticoagulant Pradaxa leads all other drugs in adverse event reports submitted to the Federal Drug Administration (FDA).  According to an analysis by the Institute for Safe Medication Practices (ISMP), in 2012 the FDA Adverse Event Reporting System received at least 3,292 reports involving problems associated with Pradaxa side effects, including bleeding problems like hemorrhaging (uncontrolled bleeding) and at least 582 deaths due to Pradaxa.

It has been on the market for the past two years and during that time it topped the list of more than 700 drugs with adverse event reports being monitored by the ISMP.

Reports of Pradaxa bleeding problems

Pradaxa (dabigatran) was introduced by Boehringer Ingelheim in October 2010.  It is marketed as the first member of a new class of anticoagulants (drugs that prevent blood clots) which is a superior alternative to warfarin for stroke prevention, as it is easier to take and requires less medical monitoring.

Warfarin, which Pradaxa was designed to replace, only received 861 adverse event reports in 2012, with 56 deaths. Xarelto (rivaroxaban), is another new medication which is part of this new class of anticoagulants as Pradaxa.  It ranked 10th among drugs most commonly associated with adverse events last year, with 2,081 reports and 151 deaths. The most common adverse events identified among users of all three anticoagulants was hemorrhaging.

ISMP’s analysis of the adverse event reports found that Pradaxa’s side effects were more lethal than those associated with warfarin. The analysis shows 18% of Pradaxa adverse events resulted in the death of the patient, compared to only 7.2% of Xarelto cases and 6.5% of warfarin cases. The group suggests that a lower dose of Pradaxa and enhanced monitoring of kidney function could reduce bleeding events in older patients.

Boehringer claims a number of studies show Pradaxa is just as safe, if not safer, than warfarin. However, there are concerns that Pradaxa bleeding problems are more difficult to treat because warfarin’s anticoagulant effects can be countered with a dose of vitamin K. Pradaxa has no known antidote, or reversal agent.

Report criticizes FDA’s warning of Pradaxa side effects

The ISMP QuarterWatch for the year 2012 criticized FDA’s handling of Pradaxa, indicating that the agency has “apparently intended to discount safety concerns” linked to the drug. The report notes that the FDA dropped a mandatory medication guide and reversed an earlier decision, so now Boehringer can claim Pradaxa is superior to warfarin. The report also notes the FDA required an unusual boxed warning on Pradaxa side effects in April, which stated that if patients stopped using the drug they could be at increased risk of stroke, but the warning fails to mention that halting Pradaxa use decreased the risk of severe hemorrhage.

“The agency took several additional actions to reassure doctors and patients that growing number of adverse event reports did not signal an important risk,” the report states, going on to outline unusual FDA steps to support Pradaxa over the last two years. “The FDA’s many actions to discount mounting safety concerns about anticoagulant adverse effects remain unexplained.”