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Many people with AFib need to take anticoagulants (sometimes called blood-thinners) to reduce the possibility of blood clots. Common reasons this type of medication may be prescribed include:

  • Heart rhythm disorders such as atrial fibrillation
  • Prior clots or clot risk
  • Previous stroke or warning stroke (TIA)
  • Prior heart attack or narrowed arteries
  • Certain congenital heart defects
  • Heart valve replacements

"Blood-thinning medicines" actually slow the blood’s ability to clot, which can help to prevent blood clots from developing and traveling to the brain, causing a stroke.

How are anticoagulants taken?

Anticoagulants are usually given by mouth. In some cases, such as in the hospital, they may be given by vein (intravenously) or injected just under the skin (subcutaneously).

Are there any common problems I should look for?

Bleeding may be a complication of taking these medications. Tell your doctor if you begin to bruise easily, or you notice unusual bleeding anywhere including gums or nose bleeds.

One type of anticoagulant, warfarin (Coumadin), requires lab work that may be done in an Anticoagulation Lab or may be done at home. The newer FDA approved anticoagulants, or novel oral anticoagulants ("NOACs"), such as dabigatran, rivaroxaban, apixaban and edoxaban generally do not require these regular lab tests to assess clotting time and thus will not be addressed in this section. 

On the pages below, you’ll find tips and insight about:

  • What is Anticoagulation?
  • What you may want to understand about your labwork
  • How often you might need to visit a lab

Understanding Warfarin

Understanding Your AFib Labwork

Learning the Basics of INR Management

Recent Lab Discussions

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    Hi fish/ken,i am not a doctor, just a fellow sufferer, so there may be technical errors in my explanation below.  My AF started during exercise, episodes would occur when I approached my max HR(183).  When i went into AF, less blood was pu...
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    Fish, you asked if i use my Fitbit while exercising. Yes i do.  Before I start a walk or bike ride i use the app for it on my phone and start it and take off.  I can see it by pushing the display button any time and when I am finished and stop the exer...
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    Hi Fish, it is very simple and important, In arrhytmias the pulse rate might be significantly lower, than heart rate. This is called pulse deficit.For more details here:
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