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 is the most important information I should know about Warfarin?

Warfarin can harm an unborn baby or cause birth defects. Do not use warfarin if you are pregnant or may become pregnant.
Never take a double dose of this medication or take it together with other products that contain warfarin or coumarin.
You should not take warfarin if you have a bleeding or blood cell disorder, blood in your urine or stools, an infection of the lining of your heart, stomach bleeding, bleeding in the brain, recent or upcoming surgery, or if you need a spinal tap or spinal anesthesia (epidural).
Warfarin may cause you to bleed more easily, especially if you have: a history of bleeding problems, high blood pressure or severe heart disease, kidney disease, cancer, surgery or a medical emergency, a disease affecting the blood vessels in your brain, a history of stomach or intestinal bleeding, if you are 65 or older, or if you are severely ill or debilitated.
Many drugs (including some over-the-counter medicines and herbal products) can cause serious medical problems or death if you take them with warfarin. It is very important to tell your doctor about all medicines you have recently used.
Ask your doctor before taking any medicine for pain, arthritis, fever, or swelling. These medicines may affect blood clotting and may also increase your risk of stomach bleeding.
Any doctor, dentist, surgeon, or other medical care provider who treats you should know that you are taking this medication.
Avoid making any changes in your diet without first talking to your doctor.

What should I discuss with my healthcare provider before taking Warfarin?

You should not take warfarin if you are allergic to it, or if you have:

hemophilia or any bleeding disorder that is inherited or caused by disease
a blood cell disorder such as anemia (lack of red blood cells) or a low level of platelets in your blood
blood in your urine or stools, or if you have been coughing up blood
an infection of the lining of your heart (also called bacterial endocarditis)
stomach or intestinal bleeding or ulcer
recent head injury, aneurysm, or bleeding in the brain
if you have recently had or will soon have any type of surgery (especially brain, spine, or eye surgery); or
if you undergo a spinal tap or receive spinal anesthesia (epidural)

You should not take warfarin if you cannot be reliable in taking it because of alcoholism, psychiatric problems, dementia, or similar conditions.
Warfarin may cause you to bleed more easily, especially if you have:

a history of bleeding problems
high blood pressure or severe heart disease
kidney disease
cancer
surgery or a medical emergency
a disease affecting the blood vessels in your brain
a history of stomach or intestinal bleeding
if you are 65 or older; or
if you are severely ill or debilitated

FDA pregnancy category X. Warfarin can cause birth defects or fatal bleeding in an unborn baby. Do not take warfarin if you are pregnant or may become pregnant. Use effective birth control and tell your doctor right away if you become pregnant while taking warfarin.
If you have any of these other conditions, you may need a dose adjustment or special tests:

liver disease
celiac sprue (an intestinal disorder)
diabetes
congestive heart failure
overactive thyroid
a connective tissue disorder such as Marfan Syndrome, Sjogren syndrome, scleroderma, rheumatoid arthritis, or lupus; or
if you have ever had low blood platelets after receiving heparin

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.

Warfarin Side Effects

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.
Stop using warfarin and call your doctor at once if you have a serious side effect such as:

pain, swelling, hot or cold feeling, skin changes, or discoloration anywhere on your body
sudden and severe leg or foot pain, foot ulcer, purple toes or fingers
sudden headache, dizziness, or weakness
unusual bleeding (nose, mouth, vagina, or rectum), bleeding from wounds or needle injections, any bleeding that will not stop
easy bruising, purple or red pinpoint spots under your skin
blood in your urine, black or bloody stools, coughing up blood or vomit that looks like coffee grounds
pale skin, feeling light-headed or short of breath, rapid heart rate, trouble concentrating
dark urine, jaundice (yellowing of the skin or eyes)
pain in your stomach, back, or sides
urinating less than usual or not at all
numbness or muscle weakness; or
any illness with diarrhea, fever, chills, body aches, or flu symptoms

Less serious side effects may include:

nausea, vomiting, mild stomach pain
bloating, gas; or
altered sense of taste

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Warfarin Interactions

What other drugs affect Warfarin?

Many drugs (including some over-the-counter medicines and herbal products) can cause serious medical problems or death if you take them with warfarin. It is very important to tell your doctor about all medicines you have recently used.
Warfarin can interact with certain herbal (botanical) products, which can increase your risk of bleeding. Do not use any of the following products without first asking your doctor:

bromelains
coenzyme Q10
cranberry
danshen
dong quai
garlic
ginkgo biloba
ginseng; or
St. John’s wort

This list is not complete and there are many other drugs that can interact with warfarin. Tell your doctor about all medications you use. This includes prescription, over-the-counter, vitamin, and herbal products. Do not start a new medication without telling your doctor. Keep a list of all your medicines and show it to any healthcare provider who treats you.

What should I avoid while taking Warfarin?

Ask your doctor before taking any medicine for pain, arthritis, fever, or swelling. This includes acetaminophen (Tylenol), aspirin, celecoxib (Celebrex), ibuprofen (Advil, Motrin), diclofenac (Cataflam, Voltaren), indomethacin (Indocin), naproxen (Aleve, Naprosyn), piroxicam (Feldene), and others. These medicines may affect blood clotting and may also increase your risk of stomach bleeding.
Do not eat large amounts of foods high in vitamin K (such as liver, leafy green vegetables or vegetable oils). Vitamin K can make warfarin less effective. Avoid making any changes in your diet without first talking to your doctor.
Avoid eating cranberries, drinking cranberry juice, or taking cranberry herbal products. Avoid herbal teas that contain tonka beans, sweet clover, or sweet woodruff.
Drinking alcohol can increase certain side effects of warfarin.

Warfarin Dosage

How should I take Warfarin?

Take exactly as prescribed by your doctor. Do not take in larger or smaller amounts or for longer than recommended. Follow the directions on your prescription label. Never take a double dose of this medication or take it together with other products that contain warfarin or coumarin.
Your doctor may occasionally change your dose to make sure you get the best results.
Take warfarin at the same time every day. Warfarin can be taken with or without food.
Avoid dieting to lose weight while taking warfarin. Tell your doctor if your body weight changes for any reason.
Call your doctor if you have any illness with diarrhea, fever, chills, body aches, or flu symptoms.
While taking warfarin, your blood will need to be tested often. Visit your doctor regularly.
Wear a medical alert tag or carry an ID card stating that you take warfarin. Any doctor, dentist, surgeon, or other medical care provider who treats you should know that you are taking this medication. You may need to stop taking the medicine for a short time if you need antibiotics, surgery, dental work, a spinal tap, or spinal anesthesia (epidural).
Store at room temperature away from heat, moisture, and light.

What happens if I overdose on Warfarin?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.
Overdose can cause excessive bleeding.

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.
Edited from everydayhealth.com

Warfarin