Warfarin is a medicine that helps prevent blood clots. Because it prevents clots, it also helps prevent heart attacks, strokes, and other problems caused by blood clots.
It's important to know how to take warfarin safely.
Warfarin is a pill that you take regularly to help prevent blood clots. Coumadin is the common brand name for warfarin.
Warfarin is often called a "blood thinner," although it doesn't really thin your blood. It works by increasing the time it takes for blood clots to form.
Warfarin also keeps an existing clot from getting larger.
Warfarin is taken to prevent serious problems that are caused by blood clots. These problems can be life-threatening. They include stroke, heart attack, and pulmonary embolism. If you are at risk for one of these problems, your doctor may prescribe warfarin for you. For example, warfarin is taken by people who:
Some people also take warfarin while they recover from certain types of surgery, such as a hip replacement.
When I take warfarin, my blood takes longer to clot.
Warfarin works by increasing the time it takes for blood clots to form.
It also keeps an existing clot from getting larger.
Continue to Why?
Taking warfarin safely is important, because it can cause bleeding problems. You will get regular blood tests to make sure you are getting the safest dose possible.
But because warfarin slows the amount of time it takes for your blood to clot, you need to be extra careful. Bleeding problems can happen when you:
I need to be careful to avoid injury when I take
It's important to avoid getting hurt while taking
warfarin. An injury may cause bleeding that is
hard to control.
It is important to avoid getting hurt while taking
warfarin. An injury may cause bleeding that is
hard to control.
Continue to How?
Warfarin causes you to bleed more quickly when you're injured. So be sure to avoid doing things that increase your chances of bleeding. These are the four main steps you need to take:
Regular blood tests will help your doctor make sure you are taking the right amount of warfarin.
Things like an infection or a small change in your diet can change the way warfarin works. So can other medicines that you are taking. That's why regular testing is so important. The tests tell your doctor whether your dose needs to be changed.
Don't change your dose or stop taking warfarin unless your doctor tells you to.
Make these changes in your life to prevent falls:
Make these changes in your home to prevent falls:
Make these changes to prevent injuries:
Taking other medicines along with warfarin can cause a bad reaction. For example, some medicines can change the way warfarin works so you bleed too easily. Or warfarin can change the way the other medicine works.
Talk to your doctor before you start or stop taking any prescription medicines, over-the-counter medicines, vitamins, or herbal products. If other doctors prescribe something for you, be sure they know that you take warfarin. Here are some examples of medicines that you need to be careful of:
Follow these safety tips for taking medicines:
What to do if you miss a dose of your warfarin
If you miss a dose of warfarin, the best thing to do is call your doctor.
He or she can tell you exactly what to do so you don't take too much or too little. That way you'll stay as safe as possible.
But here are some general rules:
Most people who take warfarin can eat normally. But make sure that you don't suddenly eat a lot more or a lot less food that is high in vitamin K than you usually do.
Vitamin K helps your blood to clot so wounds don't bleed too much.
Warfarin makes blood clots form more slowly. Suddenly changing the amount of vitamin K you eat each day could keep warfarin from working well.
How to get a steady amount of vitamin K
Foods that are medium-high to high in
Follow these general rules when you take warfarin:
If you are pregnant, do not take warfarin. Warfarin can cause miscarriage or birth defects. If you are taking warfarin, talk to your doctor about how you can prevent pregnancy.
If you think you might be pregnant, call your doctor. If you are pregnant, you will take heparin during your pregnancy.
If you plan on getting pregnant, talk with your doctor. You and your doctor will decide which medicine you will take—warfarin or heparin—while trying to get pregnant.
Call 911 if:
Be on the alert for
signs of bleeding, and call your doctor right away if:
If you are injured, apply pressure to stop bleeding. Realize that it
will take longer than you are used to for the bleeding to stop. If you can't get the bleeding to stop, call your doctor.
I should stop eating anything that contains vitamin K.
Vitamin K is an important nutrient that helps your blood clot so you don't bleed too much. You should not stop eating it altogether. You just need to keep a steady amount in your blood so your medicine can work well.
Continue to Where?
Now that you have read this information, you are ready to make sure you are taking your warfarin safely.
Talk with your doctor
If you have questions about this information, print it out and take it with you when you visit your doctor. You may want to mark areas or make notes where you have questions.
Visit the American Heart Association (AHA) website for information on
physical activity, diet, and various heart-related conditions. You can search for information on heart disease and stroke, share information with friends and family, and use tools to help you make heart-healthy goals and plans. Contact the AHA to find your
nearest local or state AHA group. The AHA provides brochures and information
about support groups and community programs, including Mended Hearts, a
nationwide organization whose members visit people with heart problems and
provide information and support.
CardioSmart is an online education and support program that can be your partner in heart health. This website engages, informs, and empowers people to take part in their own care and to work well with their health care teams. It has tools and resources to help you prevent, treat, and/or manage heart diseases.
You can set health and wellness goals and track your progress with online tools. You can track your weight, waist measurement, blood pressure, and activity. You can use calculators to help you find your body mass index (BMI) and check your risk for heart problems. You can search for a cardiologist. And you can find medicine information and prepare for your next appointment. Also, you can join online communities to connect with peers and take heart-healthy challenges.
CardioSmart was designed by cardiovascular professionals at the American College of Cardiology, a nonprofit medical society. Members include doctors, nurses, and surgeons.
Return to topic:
Other Works ConsultedAgency for Healthcare Research and Quality (2010). Blood Thinner Pills: Your Guide to Using Them Safely (AHRQ Publication No. 09-0086-C). Rockville, MD: Agency for Healthcare Research and Quality. Available online: http://www.ahrq.gov/consumer/btpills.htm.
April 10, 2013
E. Gregory Thompson, MD - Internal Medicine & Jeffrey S. Ginsberg, MD - Hematology
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Last modified on: 28 September 2013