What It's For & How To Take
Warfarin works by blocking an important step in the body’s ability to form a clot. Warfarin is considered an anticoagulant medication.
Warfarin is used to treat blood clots and prevent new blood clots from forming for many different reasons.
Certain conditions increase your risk of developing a blood clot, such as abnormal heart rhythm, a recent heart attack, heart valve replacement, and surgeries such as hip or knee replacement. Blood clots may form when there has been damage to the blood vessel, and also when blood stops moving.
Warfarin is usually taken once daily, with or without food. It is important to take warfarin at the same time each day. Your dosage of warfarin is based on your specific medical condition, response to therapy and blood test. If you have any questions about the dose you are to be taking, call your pharmacist or doctor.
This medication works best when taken on a regular basis, even when you are feeling healthy. If you forget to take a dose, take it as soon as you remember. If it is near the time of your next dose, skip it and continue with your normal dose time. Do not take a double dose to make up the missed dose.
Warfarin is available from many different generic manufacturers. Ask your pharmacist if they always use the same brand of warfarin. If your pills look different than they did last time, talk with your pharmacist before taking them.
Your doctor will have you test your blood at the lab on a regular basis. This is important to see how well the warfarin is working. Your doctor will adjust your warfarin dose based on the lab results.
Watch for signs or symptoms of minor to severe bleeding. Minor bleeding includes nosebleeds, bleeding from your gums when you brush your teeth or a minor cut that continues to bleed. If any of these persist, call your pharmacist or doctor to ask for direction. If you notice signs of more severe bleeding such as blood in your stool or urine, coughing up blood or vomiting blood, treat this as an emergency and get medical help right away.
Most Important Warnings
- Warfarin can cause major and even fatal bleeding. This is more likely to happen when you are first starting warfarin, or when you have other diseases, or when warfarin is taken with other medications. Your doctor will monitor your lab results closely, especially during the startup period. Call your doctor with any signs or symptoms of bleeding and ask your pharmacist how to help prevent bleeding.
Warnings & Cautions
- Caution while performing activities with sharp objects that may lead to bleeding, such as shaving and nail trimming. Use an electric razor when shaving and be sure you use a soft toothbrush when brushing your teeth. If you fall or injure yourself, check in with your doctor as soon as possible to make sure you do not have any internal bleeding.
- Warfarin works by blocking the production of vitamin K. Many foods have high levels of vitamin K such as green leafy vegetables, broccoli, cauliflower, brussel sprouts, and green tea. If you normally have some of these foods in your diet, continue to do so. The important thing is to be consistent. If you normally don't eat these foods, and then have a large serving, it may change how the warfarin is working in your body. Maintain a balanced diet. Talk about food with your doctor or pharmacist.
- Avoid use of alcohol while taking warfarin. Daily use of alcohol while taking this medication increases your risk of stomach bleeding.
- Always tell your healthcare providers, including your dentist, that you are taking warfarin. Some procedures require you to stop your medication to limit the chance of bleeding. Do not stop your medication on your own; your health care provider will tell you exactly when to stop and restart your medication.
- Do not use warfarin during pregnancy because it may cause serious harm to the unborn baby. If you are of childbearing age, discuss with your doctor the best option for you to keep from becoming pregnant while taking warfarin. Do not breastfeed while taking this medication.
Interactions & Side Effects
- Tell your pharmacist or doctor all your medication allergies so they may determine if warfarin is safe for you to take.
- Avoid dangerous drug interactions. Many medications have the potential to cause bleeding, and you need to know what you can and cannot take with this medication. Tell your pharmacist or doctor all the other medication you are taking, including over the counter supplements, even if you don't take them very often.
- Ask your doctor if this medication is safe to take with your current health conditions. Tell your doctor if you have any bleeding disorders, recent surgeries, a history of stomach disorder, or any liver, kidney or heart disease.
- While taking warfarin, you may feel some upset stomach, headache, nausea and experience some easy bruising. If these or any other unwanted side effects persist, contact your doctor or pharmacist to talk about it with them.
- Call your doctor right away if you have any unusual bleeding such as bleeding from your gums, a constant nose bleed or prolonged bleeding from a cut.
- Seek immediate medical attention if you notice any blood in your urine or stool or are vomiting or coughing up blood.
- Call emergency 911 if you have any symptoms of a heart attack such as chest and left arm pain, shortness of breath and sweating or if you have symptoms of a stroke such as weakness on one side of your body, slurred speech, sudden vision changes, and confusion.