In today’s epidemic of vascular embolic diseases, anticoagulation has become an important part of clinical treatment. Drugs used for anticoagulation and its role in a variety of parts, dazzling, now for you to inventory some of the commonly used in clinical anticoagulation drug classification and dosage. Indications for anticoagulant therapy Deep vein thrombosis prevention and treatment; pulmonary embolism; atrial fibrillation, artificial heart valves and cardiac thrombosis patients stroke prevention; ischemic heart disease; cardiac catheterization and plasma separation replacement. Classification of anticoagulant drugs 1, heparin class: heparin, low molecular heparin. 2, Vitamin K antagonist: warfarin. 3, Prothrombin inhibitors: dabigatran ester, hirudin, bivalirudin, argatroban, etc.. 4, Coagulation factor Xa inhibitors: sodium sulfadiazine, rivaroxaban, apixaban, etc. Heparin class Representative drugs: ordinary heparin, low molecular heparin Ordinary heparin Target: molecular weight 15000D, with similar anti-Xa and IIa coagulation factor activity. Dosage: 1. Deep subcutaneous injection: 5000～10000 units for the first time, then 8000～10000 units every 8 hours or 15000～20000 units every 12 hours. The total amount is about 30,000～40,000 units per 24 hours, and generally satisfactory results can be achieved. Intravenous injection: after the first 5000～10000 units, or 100 units/kg every 4 hours according to body weight, diluted with sodium chloride injection and applied. 3. Intravenous drip: 20,000～40,000 units per day, add to 1000 ml of sodium chloride injection for continuous drip. Before titration, 5000 units can be injected intravenously as the initial dose. 4. Prophylaxis: For patients at high risk of thrombosis, mostly used after abdominal surgery to prevent deep vein thrombosis. Give 5000 units of heparin subcutaneously 2 hours before surgery, but anesthesia should avoid epidural anesthesia, and then 5000 units every 8 to 12 hours for a total of about 7 days. Precautions: When applying heparin, it is necessary to monitor the coagulation time and APTT (about 1-2 times of the normal value of 32-43 seconds), and it is also necessary to monitor the platelets to prevent heparin-induced thrombocytopenia (HIT), and heparin overdose can be rescued by the use of cavitriol. Low molecular heparin Target: molecular weight 15000D, average molecular weight 4000-5000D, anticoagulant Xa factor effect is greater than anti-IIa factor. Usage and dosage: According to body weight, it is recommended to give 100 IU/kg/dose, subcutaneous injection once or twice a day. The greatest advantage of using this drug is that APTT monitoring is not required. 2. In patients with severe renal insufficiency, the use of normal heparin at the time of initial anticoagulation is a better choice (creatinine clearance <30 ml/min) because normal heparin is not metabolized by the kidneys. Vitamin K antagonists Representative drug: warfarin. Targets: coagulation factors II, VII, IX, X, protein S and protein C. Dosage: 1. Warfarin dosage is divided into a starting dose and a maintenance dose. Theoretically, the average starting dose of warfarin is 5 mg per day, and the INR is ≥2.0 after 4-5 days of treatment. a loading dose of warfarin is usually not required. 2. For warfarin-sensitive patients, the elderly and patients at high risk of bleeding, the starting dose should be <4-5 mg/d. 3. Depending on the dose of warfarin used, anticoagulant efficacy generally occurs 2-7 days after treatment. 4. If rapid anticoagulation is required, heparin can be given concomitantly for ≥4 days and discontinued 2 days after the INR reaches the target range. Precautions: INR should be monitored daily at the start of warfarin therapy until the INR is within the target range for two consecutive days. Monitoring should then be performed 2-3 times per week for 1-2 weeks, with monitoring tapered to once every 4 weeks after stabilization. Re-monitoring is required for dose adjustment. Thrombin inhibitors Representative drug: dabigatran etexilate. Target: Coagulation factor IIa, the final step in the "coagulation waterfall". Dosage: The recommended dose for adults is 300 mg orally daily, i.e., one 150 mg capsule twice daily. Elderly patients (>80 years of age) at risk of bleeding should be treated with 220 mg daily, i.e. 1 capsule of 110 mg twice daily. No dose adjustment is required for patients with mild to moderate renal insufficiency. Conversion from warfarin to dabigatran etexilate: Vitamin K antagonists should be discontinued. Administer when INR (International Normalized Ratio of Prothrombinogen) < 2.0. 2. Conversion from dabigatran etexilate to warfarin therapy: a decision should be made as to when to initiate vitamin K antagonist (VKA) therapy based on the patient's creatinine clearance. When CrCL ≥ 50 ml/min, initiate VKA therapy 3 days prior to dabigatran etexilate discontinuation. When 30 ml/min ≤ CrCL < 50 ml/min, administer VKA 2 days prior to dabigatran etexilate discontinuation. Coagulation factor Xa inhibitor Representative drug: sodium sulfadiazine. Target of action: Molecular weight 1725D, anticoagulant factor Xa only. Dosage: Recommended dose is 2.5 mg once daily without adjustment for body weight. Specialized Patients: It should be noted that in patients with creatinine clearance of 20-50 ml/min, the dose should be reduced to 1.5 mg once daily. Patients with creatinine clearance <20 ml/min should not be used. No dose adjustment is required in patients with hepatic impairment. Precautions: Sodium sulfadiazine does not completely inhibit Xa and does not inactivate formed IIa; therefore, it cannot inhibit contact thrombosis; therefore, sodium sulfadiazine is not used to prevent contact thrombosis during PCI, and normal heparin is still used. It is a new type of oral anticoagulant that does not require routine monitoring. Summarize 1, the target of heparin anticoagulants is related to the molecular weight: as the molecular weight decreases, the activity of anti-IIa factor also decreases, and the risk of bleeding is smaller. Bleeding adverse effects: heparin > low molecular heparin > pentose (sodium sulfadiazine). 3. Regarding intraoperative prophylaxis of contact thrombosis, heparin can be used for strongly procoagulant maneuvers, such as extracorporeal circulation, but adverse effects of thrombocytopenia are the most common among anticoagulants. Low molecular heparin can be used in weak procoagulant operation, such as coronary heart disease intervention. Sulfated heparin sodium, on the other hand, is not used for thromboprophylaxis in operations such as surgery and is also less likely to cause thrombocytopenia.