What is warfarin?
Warfarin is an anticoagulant (blood thinner). Warfarin reduces the formation of blood
clots.
Warfarin is used to prevent heart attacks, strokes, and blood clots in veins and arteries.
Warfarin may also be used for purposes other than those listed in this medication guide.
What should I discuss with my healthcare provider before taking warfarin?
Do not take this medicine if you have:
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a bleeding disorder such as hemophilia;
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a blood cell disorder such as anemia;
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a stomach ulcer or bleeding in the stomach;
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a history of aneurysm, blood clot, or bleeding in your
brain; or
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an infection of your heart, fluid or swelling around your
heart.
FDA pregnancy category X. This medication can cause
miscarriage, stillbirth, birth defects, or fatal bleeding in an unborn baby.
Do not use
warfarin if you are pregnant.
Tell your doctor right away if you become pregnant
during treatment. Use an effective form of birth control while you are using this medication.
Before taking warfarin, tell your doctor if you have:
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kidney disease;
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liver disease;
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celiac sprue (an intestinal disorder);
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a recent injury, surgery, or medical emergency;
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high blood pressure;
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severe or uncontrolled diabetes;
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polycythemia vera;
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congestive heart failure;
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cancer;
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overactive thyroid;
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a seizure disorder for which you take an anticonvulsant
such as phenytoin (Dilantin) or phenobarbital (Luminal); or
-
a connective tissue disorder such as Marfan Syndrome,
Sjogren syndrome, scleroderma, rheumatoid arthritis, or lupus.
If you have any of these conditions, you may not be able to use
warfarin, or you may need a dosage adjustment or special tests during treatment.
Warfarin may pass into breast milk and cause bleeding problems in the nursing baby.
Do not use this medication without telling your doctor if you are breast-feeding a baby.
Older adults and people who are severely ill or debilitated may have a greater risk of
bleeding while taking warfarin. Talk with your doctor about your individual risk.
Warfarin should not be given to anyone younger than 18 years old.
Tell your doctor (or dentist) that you are taking warfarin before you take an antibiotic or
before having surgery.
How should I take warfarin?
Take this medication exactly as it was prescribed for you. Do not take the medication in
larger amounts, or take it for longer than recommended by your doctor. Your doctor may
occasionally change your dose to make sure you get the best results from this medication.
Follow the directions on your prescription label.
Take each dose with a full glass of water. Take warfarin at the same time every day.
Warfarin can be taken with or without food.
Your body's response to warfarin can be affected by your diet, environment, physical
well-being, and other medicines or herbal (botanical) products you use.
Avoid dieting to lose weight while taking warfarin. Tell your doctor if your body
weight changes for any reason.
It is important to take warfarin regularly to get the most benefit. Get your prescription
refilled before you run out of medicine completely.
To be sure this medication is helping your condition, your blood will need to be tested on
a regular basis. Do not miss any scheduled visits to your doctor.
If you need to have a lumbar puncture (spinal tap) or any type of dental work or surgery,
you may need to temporarily stop using warfarin. Be sure your doctors know ahead of time that
you are using this medication.
Carry an ID card or wear a medical alert bracelet stating that you are taking warfarin,
in case of emergency. Any doctor, dentist, or emergency medical care provider who treats you
should know that you are taking warfarin.
Store this medication at room temperature away from heat, moisture, and light.
What happens if I miss a dose of warfarin?
Take the missed dose as soon as you remember, and call your doctor as soon as possible.
Do not take two doses at the same time to make up a missed dose.
Where can I get more information about warfarin?
Your pharmacist has information about warfarin written for health professionals that you may read.
What are the possible side effects of warfarin?
Get emergency medical help if you have any of these
signs of an allergic
reaction:
hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
Call your doctor at once if you have any of these serious side effects:
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skin changes or discoloration anywhere on your body;
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purple toes or fingers;
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pain in your stomach, back, or sides;
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low fever, loss of appetite, dark urine, jaundice (yellowing
of the skin or eyes);
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diarrhea, fever, chills, body aches, flu symptoms;
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easy bruising or bleeding that will not stop;
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blood in your urine;
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black, bloody, or tarry stools;
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nosebleeds, bleeding gums, coughing up blood;
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feeling weak or light-headed;
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sudden headache, confusion, problems with vision, speech,
or balance;
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sudden leg or foot pain; or
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sudden numbness or weakness, especially on one side of the
body.
Less serious side effects may include:
This is not a complete list of side effects and others may occur. Tell
your doctor about any unusual or bothersome side effect. You may report side effects to FDA at 1-800-FDA-1088.
What is the most important information I should know about warfarin?
This medication can cause birth defects in an unborn baby. Do not use
if you are pregnant.
Use an effective form of birth control, and tell your doctor if you
become pregnant during treatment.
Never take a double dose of this medication.
If you need to have a lumbar puncture (spinal tap) or any type of surgery, you may need to
temporarily stop using warfarin. Be sure the surgeon knows ahead of time that you are using this
medication.
Carry an ID card or wear a medical alert bracelet stating that you are taking warfarin,
in case of emergency. Any doctor, dentist, or emergency medical care provider who treats you
should know that you are taking warfarin.
Warfarin interacts with many other drugs, and these interactions can be
dangerous, even fatal.
Tell your doctor about all the prescription and over-the-counter
medications you use. This includes vitamins, minerals, herbal products, and drugs prescribed by
other doctors. Do not start using a new medication without telling your doctor.
You should not take acetaminophen (Tylenol), aspirin, or NSAIDs (non-steroidal
anti-inflammatory drugs) unless your doctor has told you to. NSAIDs include celecoxib
(Celebrex), diclofenac (Voltaren), ibuprofen (Motrin, Advil), indomethacin, naproxen (Aleve,
Naprosyn), piroxicam (Feldene), and others.
These medicines may affect blood clotting
and could cause serious bleeding in your stomach or intestines.
Avoid sudden changes in your diet. Vitamin K decreases the effects of warfarin. Large
amounts of vitamin K are found in foods such as liver, broccoli, brussels sprouts, spinach, Swiss
chard, coriander, collards, cabbage, and other green leafy vegetables. Do not change the amount
of these foods in your diet without first talking to your doctor.
Avoid eating cranberries, drinking cranberry juice, or taking cranberry herbal products.
Avoid drinking alcohol, which can increase some of the side effects of this
medication.
What should I avoid while taking warfarin?
You should not take acetaminophen (Tylenol), aspirin, or NSAIDs (non-steroidal
anti-inflammatory drugs) unless your doctor has told you to. NSAIDs include celecoxib
(Celebrex), diclofenac (Voltaren), ibuprofen (Motrin, Advil), indomethacin, naproxen (Aleve,
Naprosyn), piroxicam (Feldene), and others.
These medicines may affect blood clotting
and could cause serious bleeding in your stomach or intestines.
Avoid sudden changes in your diet. Vitamin K decreases the effects of warfarin. Large
amounts of vitamin K are found in foods such as liver, broccoli, brussels sprouts, spinach, Swiss
chard, coriander, collards, cabbage, and other green leafy vegetables. Do not change the amount
of these foods in your diet without first talking to your doctor.
Avoid eating cranberries, drinking cranberry juice, or taking cranberry herbal products.
Avoid drinking alcohol, which can increase some of the side effects of this
medication.
Avoid sports or activities that could result in a bruising or bleeding injury. Use extra
caution to avoid cuts when brushing your teeth or shaving.
What other drugs will affect warfarin?
Warfarin interacts with many other drugs, and these interactions can be
dangerous, even fatal.
Tell your doctor about all the prescription and over-the-counter
medications you use. This includes vitamins, minerals, herbal products, and drugs prescribed by
other doctors. Do not start using a new medication without telling your doctor. Keep a list with
you of all the medicines you use and show this list to any doctor or other healthcare provider who
treats you.
Warfarin can interact with the following herbal (botanical) products:
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bromelains;
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coenzyme Q10;
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danshen;
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dong quai;
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garlic;
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ginkgo biloba;
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ginseng; or
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St. John's wort.
Do not use any of these products without first asking your doctor.
Some of these herbal products can cause you to bleed while you are also taking warfarin.
What happens if I have an overdose of warfarin?