What is an anticoagulant?

Anticoagulants mainly fall into the following four categories: 1. Heparin, which directly acts on thrombin through antithrombin III, includes ordinary heparin and low molecular weight heparin (enoxaparin, nadroparin, daparin, etc. ), can be used clinically by intravenous injection or subcutaneous injection; 2. Coumarins are antagonists of vitamin K, which prevent vitamin K from transforming into coagulation factors II, VII, IX and X, including dicoumarin and warfarin, and are the most commonly used oral anticoagulants in clinic; 3. Hirudin, which is extracted from leech and synthesized by gene recombination, is generally used for intravenous injection; 4. New anticoagulants, such as argatroban for intravenous use, apixaban for oral use, rivaroxaban and dabigatran, have the advantages of quick onset, short half-life, few drug interactions and clear dose-effect relationship, and tend to replace traditional anticoagulants, with the only disadvantage that they are expensive.