A new pill works as well as standard treatment to prevent blood clots in the legs and lungs, a new study finds. The study focused on treatment of venous thromboembolism, a clot that forms in a vein. These clots are most dangerous when they travel to the lungs. The clots usually are treated first with injections of the "blood thinner" heparin. This is followed by warfarin (Coumadin), which acts more slowly and is given as a pill. It's tricky to get the right dose of warfarin. Using too much or too little can lead to bleeding or clots. The new study compared standard treatment with a newer pill, apixaban (Eliquis). It starts acting right away, so heparin is not needed. Nearly 5,400 people with a history of clots were randomly divided into 2 groups. One group got standard treatment. The other received apixaban. Within 6 months, 59 people taking apixaban had new blood clots, and 12 died from clots. In the standard-treatment group, 71 had new clots, and 15 died. Fifteen people taking apixaban had major bleeding, compared with 49 of those taking warfarin. The New England Journal of Medicine published the study online. HealthDay News wrote about it July 1.
By Howard LeWine, M.D.
Harvard Medical School
What Is the Doctor's Reaction?
Doctors will soon begin treating venous thromboembolism (VTE) with better and safer drugs.
VTE is the name for blood clots inside veins. It includes blood clots that form in the legs, arms or other body parts and clots that break off and travel to the lung.
A blood clot that forms in a big vein is called deep vein thrombosis. If a piece breaks off and travels to the lungs, it's called a pulmonary embolus. A blood clot in a lung can be deadly.
VTE is more common than most people appreciate. It affects more than 1 million Americans each year. About half of them require a hospital stay. Some estimates suggest that deaths may be as high as 200,000 each year in the United States.
For decades, VTE has been treated first with heparin. This drug is an anticoagulant, sometimes called a "blood thinner." It can stop a blood clot from getting larger and prevent new clots from forming. It can be given by shots under the skin or in a vein (intravenously).
In most cases, doctors prescribe warfarin (Coumadin) within a day or two after heparin therapy begins. Warfarin is an anticoagulant pill. Unlike heparin, which starts to "thin" blood right away, warfarin takes a few days to reach its full action.
Until recently, warfarin had been the only anticoagulant in pill form. It was approved in 1954.
Warfarin is low in cost. But the drug is not easy to take. Blood clots can form if the dose is too low. Bleeding can occur if the dose is too high.
Doctors adjust the warfarin dose based on blood tests that need to be done at least once every one to two months. For some people, getting the dose right can mean weekly blood tests.
Apixaban (Eliquis) offers a potentially better alternative to traditional heparin/warfarin treatment for VTE. You don't need to take shots or get an IV. And you don't need to transition from one drug to another.
Apixaban appears to cause less risk of bleeding than warfarin. And it is just as effective, this new study finds. Prior studies have shown similar results.
Apixaban also is much easier to take than warfarin. Apixaban acts within two hours, so heparin is not needed. In addition, it doesn't require dose adjustment. It comes in fixed doses. No blood tests are required for monitoring.
There are downsides to apixaban:
- It is much more expensive. A month's supply could cost 20 times as much as warfarin.
- You need to take it once every 12 hours, rather than once a day for warfarin.
- You can't miss a dose. The drug is out of your system much faster than warfarin. Because warfarin's effects last for days, being late or missing a dose is not as serious.
- You can't rapidly reverse the "blood thinning" effect of apixaban, as you can with warfarin. This could be dangerous if you had an injury with bleeding.
What Changes Can I Make Now?
Whether or not you have ever had VTE, here are some good ways to help prevent it:
- Stay physically active. At work or at home, get up from your chair often. Short walks contract the muscles in your legs that help pump blood back toward your heart.
- Drink plenty of liquids. This is especially important when you are going to be sitting for a long time, such as in an airplane.
- Move your legs. If you are bedridden and can't take frequent walks, contracting your leg muscles will help prevent blood from pooling and clotting.
- Maintain a healthy body weight. Obesity increases the risk of VTE.
If you are in the hospital for some reason, ask your doctors and nurses to make sure you are receiving measures to prevent blood clots. These include wearing special stockings or getting low-dose heparin.
What Can I Expect Looking to the Future?
Apixaban is likely to become the first choice for many people with newly diagnosed VTE. But they must commit to taking the drug on schedule. And they must be available for frequent phone calls from the doctor's office to be certain the drug is being taken as directed.
The drug also is still very new. And we know that even well-tested drugs that get approved can be found later to have previously undiscovered side effects.
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