Heart Health

Preventing blood clots: Is warfarin still right for you?

Using warfarin effectively is challenging—perhaps even more so than doctors have realized.

blood test warfarin preventing blood clots
 Image: arun011 /Thinkstock

For more than 60 years, warfarin has been a mainstay for people with atrial fibrillation. Used properly, warfarin may prevent as many as 60% of strokes related to this common heart rhythm disorder each year. But warfarin is notoriously tricky to manage because blood levels have to be kept within a narrow range to avoid side effects such as unwanted bleeding.

As a result, warfarin users must get frequent blood tests (see "What is an INR?") when they start the drug to fine-tune their dose. Once their INR values are consistently in the right range, most people scale back to testing every month or so. But a recent study suggests that people who take warfarin need to stay extra vigilant over the long term.

To continue reading this article, you must log in.

Subscribe to Harvard Health Online for immediate access to health news and information from Harvard Medical School.

  • Research health conditions
  • Check your symptoms
  • Prepare for a doctor's visit or test
  • Find the best treatments and procedures for you
  • Explore options for better nutrition and exercise
Learn more about the many benefits and features of joining Harvard Health Online »

I'd like to receive access to Harvard Health Online for only $4.99 a month.

Sign Me Up

Already a member? Login ».

Disclaimer:

As a service to our readers, Harvard Health Publishing provides access to our library of archived content. Please note the date of last review or update on all articles.

No content on this site, regardless of date, should ever be used as a substitute for direct medical advice from your doctor or other qualified clinician.

Free Healthbeat Signup

Get the latest in health news delivered to your inbox!

Sign Up
Harvard Health Publishing Logo

Thanks for visiting. Don't miss your FREE gift.

The Best Diets for Cognitive Fitness, is yours absolutely FREE when you sign up to receive Health Alerts from Harvard Medical School

Sign up to get tips for living a healthy lifestyle, with ways to fight inflammation and improve cognitive health, plus the latest advances in preventative medicine, diet and exercise, pain relief, blood pressure and cholesterol management, and more.

Harvard Health Publishing Logo

Health Alerts from Harvard Medical School

Get helpful tips and guidance for everything from fighting inflammation to finding the best diets for weight loss...from exercises to build a stronger core to advice on treating cataracts. PLUS, the latest news on medical advances and breakthroughs from Harvard Medical School experts.

BONUS! Sign up now and
get a FREE copy of the
Best Diets for Cognitive Fitness

Harvard Health Publishing Logo

Stay on top of latest health news from Harvard Medical School.

Plus, get a FREE copy of the Best Diets for Cognitive Fitness.