Blood-Thinner Pradaxa: What You Should Know
The claim by the company that the drug needs no blood-level monitoring is misguided, Moore says. "It turns out the company has had data for several years, showing the amount of anticoagulation [blood thinning] varied [from patient to patient] more than fivefold."
That means, Moore says, that "the same dose could produce widely varying effects on blood clotting. Some patients would be at extremely high risk of bleeding. Others would not get a strong enough ... effect to serve its purpose, reduce the risk of stroke."
According to the BMJ report, the company re-analyzed drug information in 2012, finding that blood-level monitoring and adjusting the dose could lower major bleeding problems by 30% or 40% compared to warfarin -- but regulators and doctors weren't informed, the report says. The company refutes this.
"The concerns are that Pradaxa was approved on the basis that it did not require monitoring," says Rita Redberg, MD, a professor of medicine at the University of California, San Francisco. Redberg wrote an editorial to accompany the analysis. "There is now new evidence that has come to light suggesting it is not safe to use it without monitoring, particularly in the elderly and those with kidney failure. The bleeding risk is higher than we first thought and the effectiveness is basically equivalent to warfarin.''
What's needed, Moore says, is for doctors to pinpoint a patient's ideal blood level and regularly check it.
What does the drug maker say?
In a press release issued in response to the report, Boehringer Ingelheim says it did study the effect of blood-level testing and dose adjusting and concluded it was not needed.
"The truth is the totality of scientific evidence does not support dosing decisions for Pradaxa based on blood levels," the statement reads in part.
Other factors, such as how well the kidneys work, affect the risk of bleeding, too, the company says.
What does the FDA say about Pradaxa?
"At this time, FDA continues to believe that Pradaxa provides an important health benefit when used as directed and recommends that health care professionals who prescribe Pradaxa follow the recommendation in the approved drug label," says Sandy Walsh, an FDA spokesperson.
The agency still thinks the drug's benefits outweigh the risks, she says.
What do experts say patients should do now?
People on the drug should ask their doctors about their individual risks and benefits, Redberg says.
"At this time, I think we should stay with what we know works, and that is warfarin," she says.
If you take an anticoagulant, don't stop taking it without talking to your doctor. Stopping it can raise your stroke risk.