Warfarin is used to prevent blood clots from forming or growing larger. It is often prescribed for patients with certain types of irregular heartbeat and after a heart attack or heart valve replacement surgery. It works by stopping the formation of substances that cause clots.

This medication is sometimes prescribed for other uses; ask your doctor or pharmacist for more information.

Warfarin comes as a tablet to take by mouth. It usually is taken once a day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take warfarin exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Continue to take warfarin even if you feel well. Do not stop taking warfarin without talking to your doctor.

CHECK WITH YOUR DOCTOR AS SOON AS POSSIBLE if you experience diarrhea or any signs of illness, such as fever. CONTACT YOUR DOCTOR IMMEDIATELY if you experience any unusual pain, swelling, or discomfort; headache; dizziness; weakness; numbness; nosebleeds; excessive bleeding from cuts; bleeding from your gums while brushing your teeth; increased menstrual bleeding; unexplained vaginal bleeding; unusual bruising; red or dark brown urine; red or black, tarry stools; a purple, dark, or spotty discoloration of your toes; sudden or severe pain in your legs, feet, or toes; or any sores or ulcers on your skin. An allergic reaction to this medicine is unlikely, but seek immediate medical attention if it occurs. Symptoms of an allergic reaction include rash, itching, swelling, dizziness, or trouble breathing. If you notice other effects not listed above, contact your doctor, nurse, or pharmacist.

IF OVERDOSE IS SUSPECTED, contact your local poison control center or emergency room immediately. Symptoms of overdose may include abnormal or excessive bleeding or bruising and blood in your vomit, urine, or stools.

Carry an identification card at all times that says you are taking this medicine. DO NOT SHARE THIS MEDICINE with others for whom it was not prescribed. DO NOT USE THIS MEDICINE for other health conditions. KEEP THIS MEDICINE out of the reach of children. IF YOU WILL BE USING THIS MEDICINE FOR AN EXTENDED PERIOD OF TIME, obtain refills before your supply runs out.

Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one. Record the date of the missed dose and tell your doctor at your next visit, since missing a dose of warfarin may alter your blood clotting tests. If you miss doses for 2 or more days, call your doctor immediately.

This medicine is an anticoagulant used to treat or prevent harmful blood clots that may occur in the veins (venous thrombosis) or lungs (pulmonary embolism), or with a type of abnormal heartbeat (such as atrial fibrillation), or following a heart valve replacement. This medicine is also used to reduce the risk of stroke and other problems in patients who have had a heart attack. It may also be used to treat or prevent other conditions as determined by your doctor.

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom). Throw away any medication that is outdated or no longer needed. Talk to your pharmacist about the proper disposal of your medication.

DO NOT TAKE THIS MEDICINE if you have had an allergic reaction to it or are allergic to any ingredient in this product. DO NOT EXCEED THE RECOMMENDED DOSE without checking with your doctor. DO NOT STOP USING THIS MEDICINE without first checking with your doctor. Laboratory and/or medical tests, including blood clotting tests, may be performed to monitor your progress or to check for side effects. KEEP ALL DOCTOR AND LABORATORY APPOINTMENTS while you are using this medicine. BEFORE YOU HAVE ANY MEDICAL OR DENTAL TREATMENTS, EMERGENCY CARE, OR SURGERY, tell the doctor or dentist that you are using this medicine. THIS MEDICINE REDUCES BLOOD CLOTTING. To prevent bleeding, avoid any sports or other activities that may expose you to a risk of bruising or serious injury. DO NOT CHANGE BRANDS of this medicine without talking with your doctor or pharmacist. DO NOT CHANGE YOUR EATING HABITS, alcohol consumption, or activity level without checking with your doctor. A change in your diet, alcohol consumption, or activity level may lead to a change in the effects of your medicine. Foods that may change the effect of this medicine are those high in vitamin K, such as liver or green, leafy vegetables (lettuce, broccoli, cabbage, spinach, kale, or collard greens). BEFORE YOU BEGIN TAKING OR STOP TAKING ANY MEDICINE, either prescription or over-the-counter, check with your doctor or pharmacist. This includes vitamins, food or dietary supplements, or over-the-counter medicines such as aspirin, ibuprofen, acetaminophen, or cold medicines. IF YOU ARE ALREADY TAKING ASPIRIN for a heart or other condition, talk with your doctor about whether or not you should continue taking it with this medicine. WHILE YOU ARE USING THIS MEDICINE, brush your teeth carefully with a soft toothbrush, floss your teeth gently, and use caution when shaving. DO NOT BECOME OVERHEATED in hot weather as this may change the effect of this medicine. CAUTION IS ADVISED WHEN USING THIS MEDICINE IN THE ELDERLY because they may be more sensitive to the effects of the medicine. FOR WOMEN: DO NOT USE THIS MEDICINE if you are pregnant. IF YOU SUSPECT THAT YOU COULD BE PREGNANT, contact your doctor immediately. IT IS UNKNOWN IF THIS MEDICINE IS EXCRETED in breast milk. IF YOU ARE OR WILL BE BREAST-FEEDING while you are using this medicine, check with your doctor or pharmacist to discuss the risks to your baby.