Drug name: Warfarin
Alias: Benzylacetone coumarin sodium Acetone coumarin sodium
Effects: This product is a kind of coumarin anticoagulant, which has the effect of counteracting vitamin K in the body.
Effects: Mainly used to prevent and control thromboembolic diseases.
Side effects: Overdose may cause bleeding.
Contraindications: Contraindicated in persons with a history of thrombocytopenia or allergy, persons with continuous coagulation disorders that occur with bleeding or severe bleeding tendency, organ damage bleeding caused by surgery, persons with acute bacterial endocarditis, persons with traumatic cerebrovascular hemorrhage and pregnant women. Use with caution in cases of hepatic or renal failure, more severe hypertension, bleeding from gastrointestinal ulcers or other tissue damage, retinal vasculopathy, and during brain and spinal cord surgery.
Under normal conditions, the body’s coagulation and anticoagulation systems are in balance, which can effectively prevent thrombosis or bleeding events from occurring. However, when some people suffer from certain diseases, blood tends to clot in the heart or blood vessels, resulting in blockage of blood vessels. In this case, anticoagulant drugs are needed to prevent thrombotic events.
Warfarin is an anticoagulant drug that acts as an anticoagulant by inhibiting the synthesis of clotting factors in hepatocytes, counteracting the effects of vitamin K, which has a clotting function, and reducing the thrombin-induced platelet aggregation reaction. Warfarin is completely absorbed orally, with predictable onset and duration of action, and has been used clinically as a major oral anticoagulant. However, the people’s knowledge of warfarin is not complete, in general, there are 4 aspects of doubt.
1, warfarin had to use?
The doctor prescribed warfarin for the old man Sun who was suffering from atrial fibrillation. He heard that he had to take blood to monitor warfarin, otherwise there is a risk of bleeding, and thought that he was normal most of the time, and only occasionally had discomfort, so why did he have to take this drug? The doctor explained to him for a long time, but could not convince him. A few months later, he suddenly had abdominal pain and fever, and his family thought it was a bad stomach and did not draw attention to it. It was only when Sun appeared to be in a coma and short of breath that he was taken to the hospital, where an examination revealed that the original intestinal necrosis was caused by an embolism of the superior mesenteric artery. Although most of the small intestine was removed through surgery, the late diagnosis and old age and frailty led to multiple organ failure and ultimately failed to save his life. In daily life, there are many examples like Sun, who had doubts about the need to use warfarin, which led to serious consequences. Warfarin is not necessary for normal people, but for people with certain diseases, it really has to be used.
After heart valve replacement Patients with heart valve lesions should be treated permanently with oral anticoagulants after surgical valve replacement, especially if the replacement is a mechanical valve. Biologic valves are significantly less likely to thromboembolize than mechanical valves, and generally 3 months of postoperative anticoagulation is sufficient.
Atrial fibrillation Atrial fibrillation is the abbreviation for atrial fibrillation. Patients with atrial fibrillation are prone to thrombus formation in the atria and can easily dislodge and wander, which can often lead to obstruction of blood vessels in the legs, brain, and internal organs and necrosis of the calves or intestines. Such patients should take warfarin for a long time.
Pulmonary thromboembolism Deep vein thrombosis and pulmonary artery embolism are collectively called pulmonary thromboembolism, which are two stages of one disease. After the occurrence of deep vein thrombosis, if not actively treated, pulmonary artery embolism is very likely to occur, which can be life-threatening in serious cases. Therefore, prophylactic medication is available for patients who have had thromboembolic disease and those at risk of postoperative thrombotic complications. Patients with myocardial infarction thrombolysis need long-term anticoagulation after thrombolysis to keep the blood vessels open. Patients at high risk of stroke need oral prevention of stroke and other thromboembolic diseases.
2.Bleeding, unavoidable?
Bleeding has become a “major problem” of warfarin use, is it really unavoidable?
The first move to prevent bleeding: monitoring INR
Warfarin can prevent thrombosis, but excessive inhibition of clotting factor synthesis can lead to bleeding disorders. Therefore, if anticoagulant drugs are controlled at a reasonable dose, the effect of preventing thrombosis in the blood vessels without spontaneous bleeding can be achieved. To do this requires accurate monitoring, which is currently the most effective way to prevent bleeding due to overdose of warfarin.
The INR, or International Normalized Ratio, is a standardized prothrombin time. The clinical finding is that whether there is an anticoagulant effect or whether there is bleeding can be determined by the magnitude of the INR value. If the INR value is too high, it will lead to bleeding; if the INR is too low, the anticoagulant effect is not good. Only when the INR is kept between 2 and 2,5, can the effect of warfarin be fully utilized without causing bleeding.
How to use warfarin correctly
As you take warfarin for a longer period of time, the INR value will change even if the dose does not increase. By monitoring whether the value of INR is between 2 and 2,5, the amount of warfarin can be adjusted, if it is higher than this value, the amount of warfarin will be reduced; if it is lower than this value, the amount of warfarin will be increased. Some hospitals currently use warfarin in fixed small doses without monitoring INR, this method should not be advocated, and some experiments have shown that this method is not only unsafe, but also ineffective.
Second tip to prevent bleeding: do not use drugs that can cause bleeding
When using warfarin, do not also apply drugs that can enhance the anticoagulant effect and cause bleeding tendency when combined with warfarin, including chemical drugs and herbal medicines.
● How to use warfarin correctly with 20 chemical drugs
Antibiotics or antibacterial drugs: Chloramphenicol, high-dose penicillin, 2nd and 3rd generation cephalosporin antibiotics, azithromycin, clarithromycin, roxithromycin, erythromycin, quinolone antibacterial drugs such as ciprofloxacin, gatifloxacin, levofloxacin, moxifloxacin and norfloxacin, sulfonamide drugs, metronidazole, certain aminoglycoside antibiotics such as gentamicin.
Lipid-regulating drugs: clofibrate, i.e. Antoine, statin lipid-regulating drugs.
Antihypertensive drugs: diazepam. Oral hypoglycemic agents: methylsulfonylurea, phenelzine.
Antacids: cimetidine, meperidine.
Antihistamines: Benadryl.
Hypnotics: chloral hydrate.
Antidepressants: promethazine.
Prostaglandin synthase inhibitors: anti-inflammatory pain, meprobamate, clomid.
Antipyretic and analgesic drugs: acetaminophen, paracetamol, antipyretic net, acetaminophen, tylenol, pepto-bismol, piriton.
Non-steroidal antipyretic and analgesic drugs: salicylate, aspirin, pautazone, etodolac, hydroxybutazone, meclofenamic acid, indomethacin.
Vitamin preparations: vitamin E. Angina prophylaxis: beniodarone.
Antigout agents: propoxur, sulfopiridone, allopurinol. Diuretics: etanercept.
Anti-arrhythmics: quinidine, amiodarone, propiamine. How to use warfarin properly Zhang Wangde &
Antimalarials: quinine.
Antipsychotics: chlorpromazine. It is a type of coumarin anticoagulant, which has antivirulence in the body
Anticoagulant: heparin.
Anti-thyroxine drug: propylthiouracil.
3, INR monitoring law how to use warfarin correctly
Monitor once before use; monitor once on the 3rd day of administration; monitor once on the 7th day of administration; then change to monitor once a week until the 4th week; after 1 month, change to check INR once a month and adhere to it for 5 months.
● Adjust warfarin dose according to INR
The recommended initial dose of warfarin for Chinese is 2,5 to 3,0 mg once daily. The target INR depends on the condition and is usually 2,0 to 3,0. The target INR can be adjusted down to 1,6 to 2,5 for elderly people older than 75 years old and for patients at high risk of bleeding.
The INR should be routinely monitored before oral warfarin is administered, and again on the third day of dosing. If the INR is below 1,5 at this time, the dose should be increased by 1/4 tablet per day; if the INR does not change significantly from the basal level, the dose can be increased by 1/2 tablet per day; if the INR does not reach the target but is above 1,5, the dose can be temporarily not increased and wait for the results of the INR measurement on the seventh day. After the INR reaches the target value and stabilizes (two consecutive times within the target range of treatment), the INR is checked every 4 weeks. if a certain INR is encountered to be too high or too low, the time of the next INR observation should be determined according to the INR value and warfarin dose adjustment. Finally, stabilize warfarin at a certain amount.
● Monitoring INR at home is not practical for now
Currently, INR testing equipment is complex and expensive, and it is not possible to make it as popular as blood pressure meters and glucose meters in the home, and INR testing also requires more specialized skills that not everyone can master. Therefore, home monitoring of INR is not yet possible.
4, when taking warfarin, can not eat vegetables?
This statement is not entirely true, although foods rich in vitamin K or can interfere with the synthesis of vitamin K, affecting the role of anticoagulant drugs, antifibrinolytic drugs and antiplatelet drugs, can affect the efficacy of warfarin, but this does not mean that patients need to completely avoid these foods, but need to maintain a relatively balanced diet, pay attention to the appropriate reduction in the intake of foods rich in vitamin K (vitamin K for adults daily intake is 65-80 micrograms), and it is not necessary to overly restrict the intake of vegetables with low vitamin K content (for example, onions have fibrinolytic activity and should not exceed 60 grams in 1 day). After all, vegetables and fruits can provide other nutrients that are necessary for the health of the whole organism.
Foods rich in vitamin K are sour cheese, pork liver, egg yolk, barley, beans, carrots, tomatoes, safflower oil, soybean oil, cod liver oil, seaweed, broccoli, green peppers, garlic, ginger, cauliflower, green leafy vegetables (spinach, rape, alfalfa, lettuce, cabbage) and pears, apples, peaches, oranges, etc. Green leafy vegetables are rich in vitamin K. The vitamin K content per 100 grams of vegetables is: 380 mg of spinach, 315 mg of dark green leafy lettuce and 145 mg of cabbage.
In fact, in addition to attention to avoid excessive intake of vitamin K-rich foods, but also in life care methods. Some people abuse antimicrobials and “detoxification bowel cleansing” health care method, disrupting the balance of intestinal flora (for example, quinolone antibiotics with broad-spectrum antibacterial properties in the killing of disease-causing microorganisms, but also to reduce the production of vitamin K and coagulation factors of intestinal beneficial flora, resulting in prolonged clotting time), easily resulting in vitamin K deficiency, these people If warfarin is used, it also tends to cause bleeding.