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Warfarin Mechanism of Action

Lesson Transcript
Instructor: Artem Cheprasov

Artem has a doctor of veterinary medicine degree.

Warfarin is a commonly used blood thinner. Learn about Warfarin and its mechanism of action by first understanding how clotting works, and then exploring Warfarin's role in that process. Updated: 01/06/2022

What Is Warfarin?

What compound is used to kill rats but save human lives? It's warfarin! Warfarin, or brand name Coumadin, is a type of blood thinner that helps minimize or disturb the proper clotting of blood. It's a very commonly used oral medication. Let's go over this drug's mechanism of action.

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  • 0:04 What Is Warfarin?
  • 0:24 Clotting
  • 1:25 Warfarin's Role
  • 2:47 Lesson Summary
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In order to understand how warfarin works, you need to know how clotting works. The complete mechanism behind the way your blood clots is extremely complex, but it goes something like this.

Your blood contains quasi-cells called platelets. They're not true cells, but they look like cells. When a blood vessel is healthy, platelets slide past the blood vessel's walls with ease. As soon as a blood vessel is injured, the platelets stick to the injured part of the wall and to one another, thereby plugging up the injured portion of the blood vessel so blood doesn't escape.

This mass of platelets is further reinforced by a net of fibrin strands. Fibrin is a type of protein critical to the formation of strong blood clots. There is an enzyme involved in all this process called thrombin, and it does two important things:

  1. It helps the platelets to stick to one another
  2. It helps to form fibrin

There are certain proteins involved in the making of the enzyme thrombin.

Warfarin's Role

And here is where we transition to warfarin's role in all of this. Warfarin stops the synthesis of vitamin K dependent factors. It does so by blocking the vitamin K epoxide reductase (VKORC1) enzyme complex, whose job it is to change a form of vitamin K into a new form that can help in activating clotting proteins. Since warfarin stops the enzyme, it can't use vitamin K to help make these vitamin K dependent factors.

These vitamin K dependent factors, which are types of proteins, are:

  • Factor II
  • Factor VII
  • Factor IX
  • Factor X
  • Proteins C and S

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