Meaning of warfarin: Warfarin thins the blood by interfering with the liver's production of clotting factors that depend on vitamin K.

Definition of warfarin

Warfarin is a medication that reduces the blood's ability to form clots. It belongs to a class of medications called anticoagulants, often referred to as blood thinners, though warfarin does not thin the blood itself so much as interfere with the chemical steps needed to form a clot.

Warfarin works by blocking the liver's use of vitamin K, which the body needs to produce several clotting factors. With less of these factors available, blood takes longer to clot, reducing the risk of unwanted clot formation in conditions such as atrial fibrillation, certain heart valve problems, and prior blood clots in the legs or lungs.

Because warfarin's effect can vary based on diet, other medications, and individual metabolism, treatment typically involves regular blood testing to measure how long blood takes to clot, allowing the dose to be adjusted to keep the effect within a target range.

Also known as

Coumadin

Used in a sentence

Warfarin was continued with regular laboratory monitoring to keep the anticoagulant effect within the target range.

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Good to know

Warfarin's effect can shift with diet and other medications, which is why clotting time is monitored regularly rather than assumed stable on a fixed dose.

For learning, not diagnosis. This glossary provides general educational information and is not a substitute for advice from a qualified healthcare professional. If you may be experiencing a medical emergency, contact local emergency services.