Patients who can use heparin are able to take oral long-acting anticoagulants, and patients who cannot use heparin are equally unable to take oral long-acting anticoagulants. Since they are anticoagulants, they have a common side effect with heparin, which is bleeding. Therefore, the patient should be noted for any bleeding tendencies, such as bleeding gums, blood in urine, etc. Prothrombin time, prothrombin activity and international standard ratio are widely used monitoring indicators. The normal value of prothrombin time is 12-14 seconds, and the normal value of prothrombin activity is 80-120%. The international standard ratios, on the other hand, vary according to the purpose of treatment, and the treatment of lower extremity deep vein thrombosis requires maintenance of 2 to 3. The amount of long-acting anticoagulant required varies greatly from patient to patient, depending on the liver function and the amount of vitamin K normally stored in each patient. Therefore, the drug should be monitored frequently after administration to figure out the optimal dose needed for each patient. This requires a prolongation of prothrombin time by more than 50% and a decrease in prothrombin time activity to 30%-40% to achieve the therapeutic goal. The internationally accepted international standard ratio (INR) is now calculated based on the sensitivity of long-acting anticoagulants produced by different pharmaceutical companies. During the use of long-acting anticoagulants, an INR of between 2 and 3 is required. The time to take long-acting anticoagulants is usually chosen in the afternoon or at bedtime, and blood is taken the next morning to measure the prothrombin time, and the results of the laboratory tests are followed up in the afternoon to determine the next dosage according to the results. Generally, twice the usual dosage is used on the first day, 1.5 times the usual dosage on the second day, and the usual dosage is changed to the third day. The test should be done once a day for a week or even longer, and the test can be changed to once a week or longer after the maintenance dosage has been determined, so that the maintenance dosage can be corrected in time until it is discontinued. Medical units that are not equipped to check prothrombin time should not use long-acting anticoagulants, and patients should not take them on their own. Certain hormonal and steroidal drugs such as prednisone, hydrocortisone, anti-inflammatory pain, bactrim and other drugs like reserpine and hypoglycemic have anti-platelet aggregation effects and can be used in conjunction with anti-platelet drugs alone. However, antiplatelet drugs can act synergistically with heparin and long-acting anticoagulants and should not be used simultaneously to avoid the side effects of increased bleeding. If these drugs must be applied simultaneously with anticoagulants, they should be applied simultaneously throughout the use of anticoagulants to facilitate monitoring of anticoagulant drugs. Some drugs such as rifampin, sodium pentothal and barbiturates can weaken the effect of anticoagulants, and when they must be combined with these drugs, the dosage of anticoagulants should be adjusted.