Warfarin is the most widely used oral anticoagulant in clinical practice and has a clear role in the prevention of thromboembolism in patients with atrial fibrillation. However, there is some risk associated with the use of this drug due to the wide inter-individual dose variation, so please refer to the information below before using it or each time you restart long-term warfarin. If warfarin is necessary for the treatment of your current disease, please take warfarin in the exact dose prescribed by your doctor, as this will reduce the chance of blood clot formation.
The most significant side effect of warfarin is bleeding, which can sometimes cause serious, even life-threatening bleeding. To maximize the therapeutic effects of warfarin while reducing the incidence of bleeding, you must.
1. Have your blood drawn regularly to test your clotting function.
The dose of warfarin you take will be adjusted based on the results of the coagulation test. The tests are PT and INR, which reflect the rate of blood clotting. During treatment, the INR will be higher than normal and should usually be between 2.0 and 3.0, but the target range your doctor has set for you may vary depending on the patient, so please check with your doctor for your target values for your recent treatment. The prevention of blood clots can only be achieved by maintaining your INR value within the appropriate range as much as possible through regular testing.
Please visit the hospital for blood tests at the designated time according to your doctor’s request, and do not decide to cancel the tests without your consent.
2. Pay frequent attention to bleeding manifestations and contact your physician immediately if you have any of the following symptoms.
Local pain, swelling or discomfort
Headache, dizziness or feeling weak
Bruising of the skin (bruising or enlargement of an injury of unknown origin)
Nosebleeds, bleeding gums
Wounds that bleed a lot or take a long time to stop bleeding
Menstrual or vaginal bleeding that is more severe than usual
Yellowish or pink, red or black urine
Coughing up blood, spitting up blood or spitting up coffee grounds-like substance
3. Many other drugs, including prescription and over-the-counter drugs, vitamins and herbs, including food, may interact with warfarin and will enhance or weaken the effects of warfarin when taken, resulting in increased side effects or reduced effectiveness
(1) These drugs include: antiplatelet agents (aspirin, etc.), statins (fluvastatin, simvastatin, etc.), antibiotics (sulfonamides, penicillins, cephalosporins, quinolones, macrolides, tetracyclines, etc.), antifungals (conazole), diuretics (spironolactone, etc.), vitamins (e.g., vitamin K), amiodarone (commonly used in the treatment of atrial fibrillation), digoxin (2) Some herbs can increase the risk of uric acid.
(2) Some herbs can increase the effect of warfarin: for example, ginkgo (ginkgo biloba), garlic (mechanism of action unclear), angelica (containing coumarin), papaya (mechanism of action unclear), salvia (decreases sodium clearance of warfarin). There are herbs that reduce the effects of warfarin, such as ginseng, and forsythia.
You should: inform your cardiologist of all medications, vitamins and herbs you are taking. Consult your cardiologist or pharmacist if you need to take new medications for other medical conditions or if you need to stop taking medications that you have been taking for a long time while you are taking warfarin. Make a list of the medications you are taking and show it to your doctor.
(3) Foods that may reduce the effects of warfarin include: green vegetables and leaves rich in vitamin K, such as: amaranth, cabbage, Brussels sprouts, endive, lettuce, green mustard, kale leaves, lettuce leaves, mint leaves, spinach leaves, celery, watercress, frangipani, cucumber skin (peeled cucumbers are not a problem), green cabbage, methion seeds, shallots, green onions, soybeans (natto), pistachios, kiwi, avocados purple lavender, and tea (tea is no problem). Some vegetable oils are also high in vitamin K, such as canola oil, olive oil, and soybean oil.
You should: maintain a normal, balanced diet, try to diversify your food groups and not concentrate on a large number of certain foods over a period of time. There is no need to deliberately reduce your consumption of green vegetables, but you should try to keep eating approximately the same amount of vegetables each day. Avoid drinking alcohol.
4.No matter where you go to see your doctor, don’t forget to tell your doctor that you are taking warfarin and bring information (such as a prescription) that shows that you are taking warfarin.
5.How should I take warfarin?
(1) Take warfarin exactly at the dose prescribed by your doctor. Your doctor will adjust the dose of warfarin according to the INR value of each test. Therefore
(2) You must have regular blood tests and tell your doctor the results so that your condition can be monitored.
(3) Take warfarin at the same time every day. It is best to take it in the afternoon so that the dose can be adjusted on the day of the test if needed. It can be taken with a meal or on an empty stomach.
(4) Please make up the dose at that time within 4 hours of forgetting to take it, and do not make up the dose beyond 4 hours; continue to take the dose normally the next day, and do not double the dose on the next day because you forgot to take it. Please write down the missed dose on your calendar and tell your doctor or pharmacist when you next visit the hospital for a follow-up.
(5) If you take an overdose of warfarin, contact your physician immediately.
(6) If you feel sick because of diarrhea, infection, or fever, go to the hospital as soon as possible.
(7) Be sure to inform your physician if you plan to have surgery or any invasive medical or dental procedures. You may have to stop taking warfarin for a short period of time or may need a dose adjustment.
(8) If you fall or injure yourself, especially if you hit your head, go to the hospital immediately and your physician may need to examine you as necessary.
6.What should I avoid when taking warfarin?
(1) Do not start, stop or change any combination of medications until you have consulted with your physician.
(2) Do not consume large amounts of something, especially large amounts of green leafy vegetables, in a short period of time.
(3) Do not change your weight through dieting until you have been examined by a physician.
(4) Avoid smoking and drinking alcohol.
(5) Do not perform any activities or sports that may lead to serious injuries.
7.What details of life should I pay attention to while taking warfarin?
Please use a soft-bristled toothbrush to brush your teeth. Because warfarin increases the risk of bleeding, you should avoid activities that could injure you. Tell your doctor, pharmacist, or nurse about your current activities and ask them if you can continue them while you are taking warfarin. Some physical activities that are usually safe include walking, jogging, swimming, and gardening. Your doctor should be made aware of changes in your exercise level, as this may also affect your INR.
8. What if I want to travel while taking warfarin?
You can travel, but you must do the following: take adequate medication with you; take your medication at the same time every day; maintain a stable diet; have your PT and INR measured before and after you go on a trip; and avoid long car and airplane rides.