Reasons to take warfarin

Why am I on warfarin?

Warfarin is used for many different medical reasons. This medicine may also be prescribed for uses that are not listed below.

Deep Vein Thrombosis (DVT) and Pulmonary Embolism (PE):

DVTs are blood clots that form in the deep veins of the legs or arms. Part of the clot may break off and go to the lung, causing a PE.

Valve Replacement:

Artificial or mechanical heart valves are very useful in replacing heart valves that do not work well. These valves are not a natural part of your body, so clotting can happen on them. If a clot forms and breaks off, a stroke can happen.

Atrial Fibrillation:

The upper heart chambers (atria) beat in a disorganized way and cause rapid, irregular heartbeats. This causes blood to pool, which may allow a clot to form. If these clots break loose, they may travel to the brain and cause a stroke.

Stroke or Cerebrovascular Accident (CVA):

A stroke is caused by a blood clot that forms in the brain. This may also be caused by another material (emboli) moving through the blood that goes to the brain. A transient ischemic attack (TIA) is a brief stroke that happens when the blood flow to the brain briefly stops.


The conditions listed below may make your blood more likely to clot:

  • Antiphospholipid antibody syndrome (lupus anticoagulant or anticardiolipin antibodies)
  • Antithrombin III deficiency
  • Factor V Leiden
  • Protein C and S deficiency
  • Prothrombin gene mutation

Peripheral Artery Disease:

This is when not enough blood gets to your legs, arms, or feet. This is caused by the arteries getting clogged and harder.

Warfarin may be used to prevent clots for other reasons too, such as:

  • Left ventricular assist device
  • After a joint replacement
Last reviewed: 
December 2021

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