When it was approved by the U.S. Food and Drug Administration (FDA) to reduce stroke risk in atrial fibrillation patients, Boehringer Ingelheim’s new blood-thinning drug Pradaxa was heralded as a long-awaited alternative to warfarin, which had been the only drug of its kind for nearly 60 years. But since Pradaxa’s October 2010 approval, many of the nation’s leading cardiologists have grown concerned that the new drug’s risks may overshadow the benefits it provides.

Dr. Alan Jacobson, director of anti-coagulation services at the Veterans Administration (VA) health care system in Loma Linda, California, told Reuters that the “good news” about Pradaxa is “you now have an alternative to warfarin.” But the “bad news,” he said, “is you can kill a patient as easily with the new drug as you could with the old drug” if it is not taken with the utmost caution.

“The average patient doesn’t understand anything about the new drug, or what the risks are, or what other medicines he can or can’t take,” Dr. Jacobson told Reuters, citing potentially deadly interactions between Pradaxa and other drugs, including common pain killers that affect the blood.

Both Pradaxa and Xarelto, another new stroke preventative jointly developed by Johnson & Johnson and Bayer, were designed to offer the benefits of warfarin without that drug’s risks. Warfarin, sold under the brand name Coumadin, requires close monitoring and routine blood tests to ensure the drug is working as it should.

Recent studies, however, suggest that patients may be much safer taking warfarin than Pradaxa. An analysis of FDA records conducted by the Institute for Safe Medicine Practices found that Pradaxa was linked to more adverse-event reports than any other drug in 2011.

That year, the FDA received 817 direct reports of adverse events linked to Pradaxa use. The manufacturer received another 2,964 adverse event reports. Reactions and complications reported to the FDA and Boehringer Ingelheim included 542 patient deaths and 2,367 cases of hemorrhaging.

By comparison, the FDA received 490 adverse event reports attributed to warfarin in 2011, while the manufacturer, Bristol-Meyers Squibb, received an additional 616 reports, which included 72 deaths.

Although some doctors caution that adverse events linked to warfarin may be underreported because the drug is decades old and the risks are well-known, the fact remains that warfarin continues to outsell Pradaxa many times over. Last year, 15 times as many warfarin prescriptions were written in the U.S. (33 million) as Pradaxa prescriptions (2.2 million).

Another giant risk of Pradaxa (and Xarelto too) is the lack of an antidote to stop the drug’s blood-thinning effects during a bleeding emergency. Doctors can bring bleeding under control in warfarin patients with relative ease by administering vitamin K to counter the drug’s effects. Serious internal bleeding in Pradaxa patients, however, requires a blood transfusion, a lengthy procedure that is of little use in an emergency.

Some doctors also urge patients who are about to start a regimen of Pradaxa or Xarelto to get their kidneys checked to make sure they are in good function and see a doctor regularly after making the switch.

Source:

Reuters

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