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Anticlotting therapy for atrial fibrillation: Should you stay with the devil you know?

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“There are pros and cons to both options.
—Dr. Christian Ruff, cardiologist

Preventing stroke with warfarin (Coumadin) can be tricky. New anticlotting drugs can help if you accept certain trade-offs—and take them exactly as directed.

When a man’s natural heart rhythm gets out of whack, often the problem is atrial fibrillation (AF)—the most common form of cardiac arrhythmia. The most important development in AF treatment in recent years is a new generation of medications to prevent AF’s main health risk: blood clots that form in the jittery upper chambers of the heart and flow downstream to the brain, causing a stroke.

These drugs (see page 7 for details) have some important advantages over the current standard of clot-prevention, warfarin (Coumadin). Benefits to you include fewer interactions with food and other drugs and less chance of serious bleeding.

“There are pros and cons to both options,” says Dr. Christian Ruff, a cardiologist at Harvard-affiliated Brigham and Women’s Hospital. “There are people who do well on warfarin and want to keep taking it. But even for them, there is a potential benefit in that the new drugs reduce the risk of bleeding in the brain.”

Even so, leaving warfarin behind isn’t best for everyone. If you have AF, ask your doctor if the new drugs are for you. And if they are, don’t shortchange yourself by just popping a better pill without also staying on top of your general heart health.

“Maintaining a healthy lifestyle significantly reduces the risk of stroke in
those with AF,” Dr. Ruff says, “and if
you don’t have AF now, a healthy lifestyle can also help you from developing this problem later.”

AF basics

AF occurs when the heart’s two upper chambers, the atria, beat rapidly and irregularly. That increases the chance that blood will stagnate in the heart and form clots, which can travel to the brain and cause strokes. AF is associated with one in five of all strokes. In those 80 and older, AF causes one in three of all strokes.

The abnormal rhythms can make you feel terrible. They may come and go, or just take hold and not stop for hours or days. Some people don’t feel anything, though tests show that their cardiac rhythms are off. A variety of treatments can help suppress the balky rhythms, but most people with AF will have to take a drug to prevent cardiac clotting and strokes.

Warfarin’s pros and cons

While warfarin has been the mainstay for preventing strokes in people with AF since the 1950s, there are now three other options:

  • apixaban (Eliquis)

  • dabigatran (Pradaxa)

  • rivaroxaban (Xarelto)

One more, edoxaban (Savaysa), was submitted for FDA approval in January 2014.

Should a man now taking warfarin stick with it? Be assured that warfarin does work, reducing the chance of stroke in those with AF by about 65%. But to use it safely and effectively, you have to accept a couple of conditions.

  • Many common foods, prescription drugs, and over-the-counter medications can interfere with warfarin’s anticlotting action. That includes green leafy vegetables (and other foods rich in vitamin K), aspirin and other anti-inflammatory drugs, and dietary supplements like high-dose vitamin E and ginkgo biloba.

  • Because foods and drugs affect warfarin’s metabolism in the body, you need to undergo regular blood tests to check your clotting function—typically as often as every week to every month. If you end up with too much warfarin in your system, it may thin the blood too much and lead to dangerous bleeding.

If that happens, you may need an injection of an antidote to reverse the drug’s effect. If you have too little warfarin in your system, then you won’t get the protection from stroke you need.

Finding the right dose

Some warfarin users prefer periodic testing despite the inconvenience because it reassures them that they are protected from clots. If a person’s warfarin levels are too high and the person experiences unwanted bleeding, an injection of antidote can reverse the drug’s effect.

But for a minority of warfarin users, it takes a lot of effort to get on the right dose and maintain a safe and effective level of anticoagulation.

“We’re constantly adjusting their doses up and down and it’s very frustrating for some people,” Dr. Ruff says. “This means some people who take warfarin may not be adequately protected from stroke.” In such cases, the new drugs offer a possible solution.

Who should switch?

Dr. Ruff says that an increasing number of people with newly diagnosed AF are opting to try the new medications. For long-time warfarin users, the potential benefit of switching depends on two key factors:

  • Are you having trouble with warfarin you would prefer to correct? Then ask about the alternatives. “If the new anticoagulants fit in with your lifestyle and budget, then I think they are an excellent option,” Dr. Ruff says.

  • Are you willing and able to take the new drugs exactly as directed, every day? Any drug, including warfarin, won’t work if you don’t take it, but the new anticoagulants can be risky if you don’t follow directions. The drugs kick in faster but wear off faster, too, if you miss a dose.

Don’t forget that age and other cardiovascular conditions also contribute to stroke risk. Even with perfect anticoagulation, people with AF are not protected completely from stroke.

“Although no one can turn back the clock on age, there are many modifiable factors that are under each person’s control,” Dr. Ruff says. “Eating a healthy and balanced diet, exercising vigorously, and abstaining from smoking dramatically reduce the risk of stroke.”

The new anticlotting drugs: Pros and Cons

Like all drugs, the new anticoagulants have benefits as well as costs. Consider these points carefully when making your decision.

Advantages

  • The new drugs prevent strokes just as well as warfarin, and with fewer interactions with drugs and foods.

  • You don’t need to adjust the dose based on clotting function tests. Once the doctor determines the proper dose, you won’t usually need to change it.

  • You don’t need to take any blood tests to measure clotting function. That makes the new drugs more convenient.

  • Clinical trials suggest that people on the new anticoagulants cut their risk of life-threatening bleeding in the brain by half, compared with warfarin.

Disadvantages

  • Using the new anticoagulants comes with more responsibility for taking them on schedule. That’s because they kick in quicker than warfarin but also wear off sooner. As a result, you may not be adequately protected from stroke if you miss a dose.

  • The drugs cost considerably more than warfarin, which could mean higher out-of-pocket costs for you, depending on your health insurance plan.

  • There is no quick way to reverse the drug’s action if you experience serious bleeding. On the other hand, the drugs do lower the risk of bleeding in the brain. That means the most dangerous complication of taking an anticoagulant (brain bleeding) may be less likely to happen in the first place.

  • The long-term safety of the new anticoagulants is not yet well established.

Posted by: Dr.Health

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