How can warfarin cause a serious bleeding tendency?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

Fibrin in blood clotting — bleeding and blood clotting Red blood cells (erythrocytes) trapped in a mesh of fibrin threads. Fibrin, a tough, insoluble protein formed after injury to the blood vessels, is an essential component of blood clots.

Warfarin causes a serious bleeding tendency by interfering with the liver's metabolism of vitamin K. This process is essential for the production of functional coagulation factors, which are proteins necessary for blood to clot.1

By inhibiting this metabolic pathway, warfarin leads to the production of defective coagulation factors. Consequently, the body's ability to form stable clots is significantly impaired, which creates a risk of uncontrollable hemorrhage. This bleeding can occur spontaneously or result from minor injuries, such as cuts or bruises. Because of this risk, patients undergoing anticoagulant therapy must have their blood levels monitored frequently to ensure the dosage remains within a safe therapeutic range.1