New Kids on the Block

As New Anticoagulants Seek to Replace Warfarin, Hospitalists Need to Know All the Facts Before Making Therapy Decisions

Thomas R. Collins; Robert Pendleton, MD; Geno Merli, MD, FHM; Gregory Maynard, MD, MSc, SFHM


The Hospitalist. 2011;15(6):1, 29-30, 32-33. 

In This Article

Warfarin's Way Out?

Data on Pradaxa for stroke prevention in nonvalvular atrial fibrillation might be encouraging, but to some experts, it's not automatically going to prove to be a superior alternative to warfarin, says Ian Jenkins, MD, assistant professor in the Division of Hospital Medicine and part of the VTE prevention team at UC San Diego.

"It is, statistically, significantly better than warfarin for nonvalvular atrial fibrillation when you look at the stroke rate, but the number needed to treat is not small—it's 172 patients a year," Dr. Jenkins says. "So, as far as looking at an individual patient and saying, 'Am I going to prevent a stroke in this person by switching them to dabigatran?' it's actually unlikely that you would. And depending on the type of institution you're at and how good they are at managing warfarin, you might be able to get a similar improvement in their stroke risk by, say, improving the quality practices for warfarin use at your hospital."

"I think a lot of people are reluctant to start it on people who are doing well on warfarin," Dr. Maynard adds. "There's a lot of people who have been fine for many years on warfarin, even though it's a tricky drug."

At Thomas Jefferson, Pradaxa's use is restricted to cardiologists, hematologists, and the hospital's vascular anticoagulation service, and a doctor outside those categories has to get a consult first, Dr. Merli says. At University of Utah Healthcare, off-label uses have to be funneled through the thrombosis service, Dr. Pendleton says.

"Our concern was that our clinicians may use the drug for off-label indications and not for atrial fibrillation, as approved by the FDA," says Dr. Merli, whose job as chief medical officer includes overseeing patient safety. "We felt that Pradaxa's a good drug, has a good track record, but our fear was, how do we control the doctors who may want to use Pradaxa for other indications that have never been studied?"

Pradaxa also is considered for use in especially complicated cases that might be unsuitable for warfarin, he says.

A major consideration for the new drugs is that, unlike warfarin, they have no proven antidote should a patient have a bleeding episode while taking them. Warfarin patients are given vitamin K to ease the bleeding, but it's not so simple with the new medications.

Dr. Merli expects those concerns will have a "big impact on physician utilization of these new agents."

"[These are] drugs that don't require monitoring, drugs that have very little drug-drug interaction, and drugs that have no food interaction; a drug where you give a fixed dose and the patients get the same effect anticoagulation-wise."

Experts say the main option in the event of a bleed on the new agents, at least for now, is to simply wait it out while giving the patient fresh frozen plasma.

"What if you fall down and hit your head and you bleed into your brain?" Dr. Merli asks. "I'm waiting for our first patient to come in, you know, with a massive brain bleed on Pradaxa." The hospital, he notes, probably would treat with fresh frozen plasma, but then resort to Factor VII, which costs $10,000 to $12,000 per treatment.

Dr. Merli also says that the test recommended by Boehringer for assessing the degree of anticoagulation (the ecarin test) is not widely available. "That test is not available even at our hospital in Philadelphia," he says. "The companies that make them tell us that in the case of Pradaxa, you can use the [activated] partial thromboplastin time as a measure of the degree of anticoagulation, but in the studies, there was no correlation."

Then there is the cost hurdle. Warfarin, even with one or two blood tests a month to monitor international normalized ratio (INR) and assess its effectiveness, costs patients a total of $15 to $50 a month out of pocket. Paying cash for dabigatran is about $200 a month.

"Some sites haven't added it to their formulary because they were concerned that it could get started in the hospital and then the patient might not be able to obtain it outside of the hospital, and then they would end up on no anticoagulation for a period of time," Dr. Jenkins says.

On the flipside, dabigatran use could shorten hospital stays, saving costs.

If you look at the top three or four adverse drug events that occur, usually warfarin is one of those. … It's common, it's a safety issue, it's tricky to use— all of those things add up to something that hospitalists need to pay attention to.

Patients on warfarin typically have to be weaned off faster-acting IV heparin first, then weaned onto warfarin. It also can take time to make sure anticoagulation is at the proper level, also extending the stay.

Boehringer Ingelheim spokeswoman Moses notes that the company is taking steps to address the cost. "Pradaxa is now included at the lowest branded copay level on formularies that insure about 35 percent of NVAF patients [Irregular heartbeat in a patient without a diseased, repaired, or replaced mitral heart valve] in the U.S.," she wrote in an email. "For those patients who may not otherwise be able to afford treatment, BIPI [Boehring Ingelheim] offers patients assistance programs to help provide coverage for the cost of their medications."

Dr. Merli expects the majority of physicians will take a wait-and-see approach to the new anticoagulants.

"I think 20 percent will adopt the drug early," he says. "Then there's that big group in the middle, 60 percent, that will wait and see and they'll start using it. And then there's that end group of 20 percent that will never use the drug."


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