Warfarin is an oral anticoagulant drug, which inhibits the activation of clotting factors, inhibits the formation of new thrombus, limits the expansion and extension of thrombus, inhibits the formation of new thrombus on the basis of old thrombus, and inhibits the occurrence of thrombus dislodgement and embolism, and facilitates the removal of already formed thrombus. 1.What diseases is warfarin used to treat? Atrial fibrillation Aortic valve, mitral valve, tricuspid valve and other valve replacement after pulmonary artery embolism Lower limb deep vein thrombosis 2, use: The average maintenance dose of warfarin for national population is 2.98mg; the average maintenance dose of warfarin for patients ≥ 75 years old (2.3mg) is significantly lower than that for patients < 75 years old (3.02mg), and for women (2.2mg) is less than that for men (3.62mg) . The initial dose recommendation is 2 to 3 mg, and loading doses are not generally given. It can be taken once a day at any time of the day (regardless of before or after meals), but it is recommended to take it at the same time of night. The dose can be made up within 4 hours after forgetting to take it, but please do not make up the dose if it exceeds 4 hours. Do not double your medication on the second day because you forgot to take it the day before.