It is without question that blood thinners come with coherent risks. But for years, it has been said that the benefits of the medications outweigh the risks involved. However, the blood thinner industry is evolving, and now, some are concerned about a new class of blood thinners that include Pradaxa.
According to Reuters, a number of doctors interviewed said they were hesitant to prescribe the new generation blood thinners, including Pradaxa and Xarelto, because of concerns regarding the risk of stroke, serious bleeding and blood clots, particularly in patients with poor kidney function.
Pradaxa, a twice daily pill, manufactured by Boehringer Ingelheim was approved by the U.S. Food & Drug Administration (FDA) in October 2010 to prevent strokes in patients with an irregular heartbeat called atrial fibrillation. It was the first new oral treatment for that use since warfarin was introduced in the 1950s.
Xarelto, manufactured by Johnson & Johnson, was also approved for atrial fibrillation, in November 2011, and it is a once daily pill. Both were meant to be alternatives to decades-old warfarin, which requires regular blood monitoring as well as lifestyle and dietary changes. Makers of the drugs also say there was far less evidence in trials of brain bleeding with Pradaxa and Xarelto compared to warfarin.
But Pradaxa or Xarelto do come with their own issues. Doctors interviewed by Reuters said that patients using either drug should undergo testing ahead of time make sure their kidneys are functioning well. They also said patients should be educated about the drugs’ potential dangers and be seen by doctors periodically, especially after a switch is made from warfarin.
Like any blood thinner, Pradaxa and Xarelto can cause serious internal bleeding. But unlike warfarin, there is no known antidote for either Pradaxa or Xarelto bleeding. According to Reuters report, that has some doctors concerned.
“What really compounds the matter is the lack of a specific antidote to reverse life-threatening bleeding” from the drugs, Dr. Sanjay Kaul, a cardiologist at Cedars-Sinai Medical Center in Los Angeles, told Reuters. Kaul said he’s heard from about a dozen doctors about Pradaxa bleeding, most of which involved cases where the patients’ kidneys weren’t tested prior to starting the drug. Weak kidneys allow Pradaxa to build to unsafe levels in the bloodstream.
“The good news is you now have an alternative to warfarin,” said Dr. Alan Jacobson, director of anti-coagulation services at the Veterans Administration (VA) healthcare system in Loma Linda, California. “The bad news is you can kill a patient as easily with the new drug as you could with the old drug” if it is not handled properly.
The makers of Pradaxa and Xarelto say it takes time for doctors to get up to speed on new types of treatments and how to best administer them outside the controls of clinical trials.
“This is a shift in medical practice,” said Dr. John Smith, senior vice president for clinical development at Boehringer. “Individual physicians have to determine what the follow-up plan will be, to use common medical-sense judgment.”
Dr. Peter Wildgoose, a senior director of clinical development at J&J, said the company has not provided special advice on follow-up care for patients on Xarelto.
“There’s nothing more than for any other drug that people regularly take,” he said, adding that most atrial fibrillation patients probably see their doctors on a regular basis. “These drugs have been tested long term, for several years at a time, with very good outcomes.”
Boehringer Ingelheim and Johnson & Johnson officials stressed there was far less evidence in trials of brain bleeding – the most worrisome side effect of anti-coagulants – in patients taking Pradaxa and Xarelto than those taking warfarin.