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 not listed in this medication guide.

Warfarin can cause birth defects or fatal bleeding in an unborn baby. Do not use if you are 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.

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. This medication can cause 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 effective birth control while you are using this medication.

To make sure you can safely take warfarin, tell your doctor if you have any of these other conditions:

• 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.