In recent years, with the improvement of living standards, the incidence of vascular disease has increased year by year, and the number of people who need to take warfarin has also increased. An all-round understanding of warfarin and the correct use of warfarin is of great significance.
1.Why do we need warfarin?
Most of the vascular stenosis diseases are related to the hypercoagulable state of blood; blood coagulation forms thrombus, which is fixed in the local area leading to blockage or narrowing of the blood vessel there, and shedding causes embolism of the distant blood vessels, and the common result is that the blood flow of the blood vessel behind the thrombus decreases or even disappears, and the lighter tissue ischemia (such as angina), the heavier necrosis (such as myocardial infarction, stroke) occurs. The role of warfarin is to change the hypercoagulable state of blood and prevent thrombosis. Long-term oral warfarin can prevent stroke, heart attack, venous thrombosis and other thromboembolic diseases.
2.Why can warfarin anticoagulate?
Vitamin K is the raw material for the manufacture of coagulation factors in the liver. Warfarin can competitively counteract the effect of vitamin K, inhibit the synthesis of coagulation factors in hepatocytes, and also reduce the platelet aggregation reaction induced by thrombin, thus having anticoagulation and anti-platelet aggregation functions. After taking the drug, it usually takes effect after half a day, reaches the peak of anticoagulation in 1 to 2 days, and is maintained for 3 to 6 days.
3.Who should take warfarin?
The main role of warfarin is anticoagulation, for those patients who need long-term continuous anticoagulation, including the following categories.
(1) Patients with myocardial infarction treated with thrombolysis or stenting who need long-term anticoagulation to keep the blood vessels open.
(2) Patients with atrial fibrillation who require long-term anticoagulation to prevent intra-atrial thrombosis.
(3) Patients with valvular lesions or after valve surgery to prevent supravalvular thrombosis.
(4) Patients with deep vein thrombosis need long-term anticoagulation to prevent recurrence of thrombosis after thrombolytic therapy.
(5) Treatment of patients with cerebral infarction with preventive medication.
Warfarin is a double-edged sword, used properly is undoubtedly a good drug, used indiscriminately, adverse reactions are very hurtful.
4, warfarin have what adverse reactions?
(1) bleeding: everything is the opposite, the normal dose of warfarin can anticoagulate, an overdose will easily lead to a variety of bleeding. Early manifestations include petechiae, purpura, gum bleeding, epistaxis, blood in urine, wound bleeding for a long time, excessive menstrual flow, etc.. Bleeding can occur anywhere, especially in the urinary and digestive tracts; if it occurs in the brain, the results can be catastrophic. The earliest and most common manifestation is bleeding from the gums in the morning when brushing the teeth. Once bleeding occurs, warfarin has to be reduced, discontinued, and sometimes even hemostatic drugs are used. Warfarin overdose leads to consequences that go far beyond those caused by the bleeding itself; rather, anticoagulation cannot continue to cause it, and blockages in the coronary arteries, carotid arteries, and arteries in the brain may occur again.
(2) Other: relatively rare adverse reactions include nausea, vomiting, diarrhea, pruritic rash, allergic reactions and skin necrosis. Large oral doses may cause bilateral breast damage, microangiopathy or hemolytic anemia, and extensive skin necrosis; it is especially dangerous when taken in large doses at one time.
5.How to monitor the drug in general? How to adjust the medication?
The ability of each person’s liver cells to produce clotting factors is different; the sensitivity of warfarin varies greatly from person to person; and the potency of warfarin varies from batch to batch; even for the same person and the same batch, the potency of warfarin may change with other drugs or changes in physical condition. Therefore, when taking warfarin orally for a long time, it must be monitored regularly and adjusted constantly. The main indicator for monitoring is the INR (International Normalized Ratio). Treatment generally requires an INR of 2.0-3.0. an INR that is too low does not have the full effect of anticoagulation and needs to be increased. an INR that is too high carries the risk of bleeding and needs to be reduced. Because it takes 5-7 days for the efficacy of warfarin to stabilize, the INR should be measured twice a week for 2 weeks until the INR is adjusted satisfactorily. After that, the INR can be checked once a month. Check INR on the equipment requirements are not high, general medical units can test.
6.Caution.
In order to achieve the ideal anticoagulation strength, it is often adjusted to one and a half, one tablet plus 1/3, or even one tablet plus 1/4 per day orally; and the ratio of warfarin dose and INR is not a positive relationship. At this point, it is very important to divide the tablets accurately; if one tablet plus 1/3 is supposed to be taken as little as one tablet a day, and this 1/3 is divided into larger portions, actually close to half a tablet, and taken for a long time, it may be too much and lead to bleeding.