After taking warfarin for a period of time, the patient needs to be reviewed in the hospital. The INR mentioned above is the most important indicator. Patients with pulmonary embolism need to adjust the value of INR to between 2 and 3. When the INR value exceeds 3, the patient’s risk of bleeding increases; when the INR value is below 2, the patient is in a hypercoagulable state and prone to thrombosis. So not too high and not too low is appropriate. However, patients are not required to keep the INR constant to a value, as long as it is within the specified range. Generally, patients need to go to the hospital for a comprehensive examination after three months of treatment to assess the dissolution of thrombus, the adverse reactions during the medication, and to determine whether there is pulmonary hypertension caused by thrombus. In addition to checking the coagulation function, the patient needs to undergo ultrasound of the lower extremities, cardiac ultrasound, and nuclear pulmonary ventilation and perfusion scan to understand the dissolution of the blood clots in the lower extremities, whether there are any problems with the heart, and whether the blood clots in the lungs are completely dissolved. Through the evaluation, the doctor will decide whether the patient needs to continue taking medication. If the thrombus is caused by a fracture and the patient has been bedridden for too long after surgery, after three months of anticoagulation, the patient’s thrombus has basically dissolved and the medication may be discontinued; for thrombosis of unknown origin, the patient will first take anticoagulants for three months and if the patient experiences bleeding within three months, the medication will be discontinued; if there is no bleeding, the medication may be taken for life. Pulmonary embolism formed by a hypercoagulable state due to a tumor, these patients also need to take the drug for life. The patient will be reviewed for as long as warfarin is taken. Patients must be reviewed in the hospital if they experience bleeding while taking the drug. The most common side effect of taking anticoagulants is bleeding. Some bleeding is not cause for alarm, while others need to be checked immediately in the hospital. What bleeding should not be alarming? If you have bleeding gums, bleeding spots on your skin, or blood in your sputum, check your INR first. If it is high, don’t stop the medication, reduce the dose a little, and review it regularly. If there is red color of urine, blood on the stool or black stool, or even gastrointestinal bleeding such as vomiting blood, you need to go to the hospital immediately for examination and tell the emergency doctor that you are taking warfarin so that he can take effective treatment measures in time. Bleeding caused by warfarin can be treated with vitamin K injections to counteract it. However, patients are not advised to stop taking the drug without permission. Patients with pulmonary embolism who usually have high blood pressure must monitor their blood pressure regularly to prevent intracranial hemorrhage. There are also some tests and treatments that should not be done as much as possible during the medication period, and if they must be done, they need to explain their medication to the doctor so that the doctor can take appropriate treatment before proceeding: 1. Patients should try not to pull out teeth during the medication period. 2. If patients are going to have surgery, warfarin should be stopped for at least one week, regardless of the size of the surgery. 3. Patients should not do invasive examinations such as gastroscopy or colonoscopy, which can cause bleeding if some tissues need to be removed for biopsy.