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Aspirin, Coumadin Make Strokes Milder

Message to Atrial Fibrillation Patients: Know Your INR
WebMD Health News

Sept. 10, 2003 -- Aspirin and Coumadin lower the risk of stroke for people with atrial fibrillation. And when people taking these blood-thinning drugs do have a stroke, it's milder.

Nearly all the milder strokes happened in patients whose INR value was at 2.0 or more. The INR is a measure of how well blood thinners are working. The higher the INR, the greater the blood-thinning effect of the drug.

The new findings come from a study of 13,559 atrial fibrillation patients who suffered strokes. Massachusetts General Hospital researcher Elaine M. Hylek, MD, and colleagues compared the patients' use of aspirin and Coumadin, their INR values, the severity of their strokes, and their 30-day death rates.

"Patients with atrial fibrillation and an INR of less than 2.0 who had an ischemic stroke [a stroke caused by a blood clot] faced a risk of death within 30 days that was more than 30 times the risk among patients with an INR of 2.0 or greater," Hylek and colleagues report in the Sept. 11 issue of The New England Journal of Medicine.

Fluttering Hearts Need Thinner Blood

Atrial fibrillation is the irregular contraction of the upper chambers of the heart. This makes the heart muscle flutter and beat abnormally. People with this condition are at enormously increased risk of stroke because blood clots can form within the heart chambers and travel to the brain. But blood-thinning medicines minimize this risk by reducing the formation of clots.

Blood thinners are recommended for nearly everyone with atrial fibrillation. In the Hylek study, the outcomes of patients taking aspirin when they had a stroke was similar to patients taking Coumadin and whose INR was less than 2. The data indicate that an INR of less than 2 will substantially increase the likelihood of death and the severe disability from atrial fibrillation-related stroke.

"It is very unusual to have a stroke when on [blood-thinning] therapy," Hylek says in a news release. "This study shows that it is possible to reduce the severity and complications for patients who do experience this uncommon event."

Precautions for Patients Taking Coumadin

Coumadin, known generically as warfarin, is a very potent blood thinner. Taking this drug means taking certain precautions.

Many medications and dietary supplements can affect the way warfarin works. These may include:

  • Prescription medications
  • Nonprescription medications such as aspirin, nonsteroidal anti-inflammatory drugs or NSAIDs (some examples are ibuprofen, naproxen, and ketoprofen), cough or cold remedies, and medications for pain or discomfort
  • Herbal products, natural remedies, and nutritional supplements
  • Products containing vitamin K

Before taking any new medication, including over-the-counter medication or medication prescribed by another doctor or dentist, check with the doctor who monitors your warfarin medication.

Your warfarin doctor may need to adjust your warfarin dosage or may recommend another medication less likely to interfere with warfarin.

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