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

Warfarin (Coumadin) decreases the blood clotting tendency by interfering with blocking the body's blood clotting substances.

Understanding Your AFib Labwork

If you are taking warfarin, your doctor will ask that you regularly monitor the blood-clotting level to be sure your medication is working and the dose of warfarin is correct.

Learning the Basics of INR Management

It is important to monitor the INR (international normalized ratio) to make sure that the level of warfarin remains in the effective range.

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