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Blood Clot Prevention Breakthrough

Coumadin Now Considered First-Line Treatment to Reduce Risk of Recurrent Blood Clots
WebMD Health News

Feb. 24, 2003 -- Long-term, very low doses of the blood-thinning drug Coumadin can greatly reduce the recurrence of life-threatening blood clots, especially a kind called deep vein thrombosis, new research shows.

It is the first study of its kind, performed by a group of Harvard researchers, and appears in the April 10 New England Journal of Medicine. The finding points to "an inexpensive and safe therapy" to prevent blood clots, according to a news release.

Deep vein thrombosis, or DVT, occurs during inactivity, such as after surgery or serious illness, or on long flights. These blood clots often recur after patients have completed therapy for a prior clot. Women taking birth control pills are also at high risk of developing DVT.

Based on this finding, Coumadin is now considered the first safe method to prevent these blood clots, writes lead investigator Paul Ridker, MD, director of the Center for Cardiovascular Disease Prevention at Brigham and Women's Hospital in Boston.

In fact, the study was halted early because of the positive results so patients would not be placed at greater risk of clot recurrence.

In deep vein thrombosis (DVT), a blood clot develops in one of the deep veins near the center of the leg. The clot may partially or completely block blood flow through the vein. Symptoms include pain, swelling in the leg, enlargement of the superficial veins, reddish-blue discoloration of the skin, and warm skin.

If the clot travels to the lungs, it can cause a life-threatening condition called pulmonary embolism.

For about four years, Ridker and colleagues tracked the progress of 508 patients, all with a history of blood clots, at 52 clinical sites in the U.S., Canada, and Switzerland. During this random study, half were given low-dose Coumadin to take daily and half were given a placebo. Of the 253 patients taking a placebo, 37 had blood clots, compared with 14 of the 255 taking Coumadin.

Coumadin reduced blood clot risk by 64%, reports Ridker.

The study's results "strongly suggest" that long-term use of low doses of Coumadin should be considered the new treatment of choice to prevent blood clots, Ridker says in a news release.

The current treatment for DVT and pulmonary blood clots is the drug heparin, followed by a full dosage of Coumadin. However, this therapy can only extend up to six months because of risk of bleeding. Once this treatment is halted, up to 9% of patients will develop more blood clots.

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