Warfarin is a commonly used oral anticoagulant in clinical practice. The therapeutic window of Warfarin is narrow; the efficacy of the drug varies greatly from patient to patient and should be adjusted according to the patient’s laboratory results – international standardized ratio and under the guidance of the doctor. I. If your doctor and you decide to take Warfarin, please pay attention to the following aspects: 1. You need to take the medication regularly every day according to the doctor’s prescription, and if you miss one dose you should make up the dose immediately the next day. If you forget to take it, do not take a double dose the next day, record and inform the doctor of the number of missed doses. If you miss a dose for more than three days, you need to readjust the dose according to the laboratory index. 2. Before Warfarin reaches the therapeutic level, the dose should be adjusted under the guidance of the doctor and the coagulation index should be monitored 2 – 3 times a week. In case of long-term treatment, INR should be measured about every 4 weeks, and any fluctuation should be notified to the doctor, and the dosage of Warfarin should be adjusted according to the laboratory index. 3. Because vitamin K is an antagonist of warfarin. You should restrict the consumption of foods that are high in vitamin K. For example, pork, milk, cabbage, lettuce, asparagus, broccoli, cauliflower, cheese, mustard, spinach, white radish, yogurt, soy products, bean sprouts. Regular consumption of these foods may affect the anticoagulant effect of Warfarin and cause instability in prothrombin time (PT) levels. Therefore, you should pay attention to dietary balance while taking Warfarin. 4. Avoid intramuscular injections and doing activities that may cause injuries during the treatment period. Avoid traumatic injuries such as falls and collisions. Use a soft-bristled toothbrush to brush your teeth, do not floss, and prevent gum bleeding. Do not use ordinary razor blades; use electric razor instead. After venous and muscle puncture, more pressure is needed to prevent bleeding and hematoma formation at the puncture site. 5. Warfarin is prone to bleeding when overdosed, and bleeding may be very serious, such as intracranial hemorrhage, chest and abdominal cavity bleeding. Early symptoms of drug overdose: hematuria, bleeding gums, menstrual flow and black stool. If there are signs of abnormal bleeding or bruising seek medical attention promptly. 6. You should not increase, stop or change any of your medication without the advice of your doctor while taking Warfarin. This is because aspirin, ibuprofen, bupropion, chloramphenicol, metronidazole, cimetidine, etc. will enhance the effect of Warfarin and increase the risk of bleeding; while alcohol, phenobarbital, estrogen-containing oral contraceptives, vitamin K, etc. will reduce the effect of Warfarin. 7. It is not recommended to frequently switch between different manufacturers of Warfarin, the products whose bioavailability will vary. If there is a switch, the dosage needs to be readjusted under the guidance of a doctor. 8. Patients should carry anticoagulant medication use cards with them during anticoagulation therapy. Before undergoing dental treatment or other surgical procedures, the doctor should be informed that he/she is receiving Warfarin treatment. If you have any of the following conditions, you should stop the medication and go to the hospital immediately: 1. bleeding while brushing your teeth or after a cut; 2. unexplained bruising that is expanding; 3. coughing up blood, vomiting blood, bloody urine, bloody stool or black stool; 4. severe headache, abdominal pain; 5. severe skin rash, skin necrosis.