Warfarin

Warfarin may cause serious bleeding that can lead to death. Tell your doctor if you have or have ever had a condition that causes you to bleed more easily than normal high blood pressure; heart attack; angina (chest pain or pressure); heart disease; pericarditis (swelling of the lining around the heart); endocarditis (infection of the heart); a stroke or ministroke; aneurysm (weakening or tearing of a blood vessel); anemia (low number of red blood cells in the blood); cancer; chronic diarrhea; or kidney, or liver disease. Also tell your doctor if you fall a lot or if you have had a serious injury or surgery recently. People over 65 years of age have a higher chance of bleeding while taking warfarin. Bleeding is also more likely if you take a high dose of warfarin or take it for a long time. The risk for bleeding while taking warfarin is also higher for people participating in an activity or sport that may result in serious injury. Tell your doctor and pharmacist if you are taking or plan to take any prescription or nonprescription medications, vitamins, nutritional supplements, and herbal or botanical products, as some of these products may increase the risk for bleeding while you are taking warfarin. If you experience any of the following symptoms, call your doctor immediately: pain, swelling, bleeding that won't stop, nosebleeds, bleeding gums, coughing or throwing up blood or material that looks like coffee grounds, easy bruising, increased menstrual flow or vaginal bleeding, pink, red, or dark brown urine, red or tarry black bowel movements, headache, dizziness, or weakness.

Some people may respond differently to warfarin based on their heredity or genetic make-up. Your doctor may order a blood test to help find the dose of warfarin that is best for you.

Warfarin prevents blood from clotting so it may take longer than usual for you to stop bleeding if you are cut or injured. Avoid activities or sports where you could get injured. Call your doctor if you have unusual bleeding or if you fall and get hurt, especially if you hit your head.

Keep all appointments with your doctor and the laboratory. Your doctor will order a blood test (PT [prothrombin test] reported as INR [international normalized ratio] value) regularly to check your body's response to warfarin.

If your doctor tells you to stop taking warfarin, the effects of this medication may last for 2 to 5 days after you stop taking it.

Your doctor or pharmacist will give you the Medication Guide. Read the information carefully and ask your doctor or pharmacist if you have any questions. You can also visit https://www.fda.gov/downloads/Drugs/DrugSafety/ucm088578.pdf to obtain the Medication Guide.

Talk to your doctor about risks of taking warfarin.

Warfarin is used to:

• prevent and treat blood clots
• prevent complications in people with certain types of irregular heartbeat, people with prosthetic (replacement or mechanical) heart valves, and people who have had a heart attack or stroke.

Warfarin is in a class of medications called anticoagulants ('blood thinners'). It works by decreasing the clotting ability of the blood.

Warfarin comes as a tablet to take by mouth. Take once a day with or without food. Take warfarin at around the same time every day.

Take warfarin exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor. Call your doctor immediately if you take more than your prescribed dose of warfarin.

Your doctor will probably start you on a low dose of warfarin and gradually increase or decrease your dose based on the results of your blood tests. Make sure you understand any new dosing instructions from your doctor.

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

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

Before taking warfarin,

• tell your doctor or pharmacist if you are allergic to this drug, any part of this drug, or any other drugs, foods or substances. Tell your doctor or pharmacist about the allergy and what symptoms you had.
• do not take two or more medications that contain warfarin at the same time. Be sure to check with your doctor or pharmacist if you are uncertain if a medication contains warfarin or warfarin sodium.
• tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, and nutritional supplements you are taking or plan to take while taking warfarin. Your doctor may change the doses of your medications or monitor you carefully for side effects.
• the following nonprescription or herbal products may interact with warfarin: coenzyme Q10 (Ubidecarenone), Echinacea, garlic, Ginkgo biloba, ginseng, goldenseal, and St. John's wort; omeprazole; famotidine; aspirin and nonsteroidal anti-inflammatory drugs (NSAIDS) such as ibuprofen or naproxen. Be sure to let your doctor and pharmacist know that you are taking these medications before you start taking warfarin. Do not start any of these medications while taking warfarin without discussing with your healthcare provider.
• tell your doctor if you have or have ever had diabetes. Also tell your doctor if you have an infection, a gastrointestinal illness such as diarrhea, or sprue (an allergic reaction to grains that causes diarrhea), or an indwelling catheter (a soft plastic tube placed into the bladder to help drain urine out).
• tell your doctor if you are pregnant, think you might be pregnant, or plan to become pregnant while taking warfarin. Talk to your doctor about the use of effective birth control while taking warfarin. If you become pregnant while taking warfarin, call your doctor immediately. Warfarin may harm the fetus. If you take warfarin with a mechanical heart valve, talk to your doctor about the risks and benefits of continuing warfarin during pregnancy.
• tell your doctor if you are breast-feeding.
• if you are having surgery, including dental surgery, or any type of medical or dental procedure, tell the doctor or dentist that you are taking warfarin. Your doctor may tell you to stop taking warfarin before the surgery or procedure or change your dosage of warfarin before the surgery or procedure. Follow your doctor's directions carefully and keep all appointments with the laboratory if your doctor orders blood tests to find the best dose of warfarin for you.
• ask your doctor about the safe use of alcoholic beverages while you are taking warfarin.
• tell your doctor if you use tobacco products. Cigarette smoking may decrease the effectiveness of this medication.

Eat a healthy diet. Some foods and beverages that contain vitamin K can affect how warfarin works. Ask your doctor or pharmacist for a list of foods that contain vitamin K. Eat consistent amounts of vitamin K-containing food on a week-to-week basis. Do not eat large amounts of leafy, green vegetables or certain vegetable oils that contain large amounts of vitamin K. Be sure to talk to your doctor before you make any changes in your diet. Talk to your doctor about eating grapefruit and drinking grapefruit juice while taking this medication.

Take the missed dose as soon as you remember it, if it is the same day that you were to take the dose. Do not take a double dose the next day to make up for a missed one. Call your doctor if you miss a dose of warfarin.

Warfarin may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

• gas, bloating
• abdominal pain
• change in the way things taste
• loss of hair
• feeling cold or having chills

If you experience any of the following symptoms, or those listed in the IMPORTANT WARNING section, call your doctor immediately:

• hives, rash, itching
• difficulty breathing or swallowing
• swelling of the face, throat, tongue, lips, or eyes
• hoarseness
• chest pain or pressure
• swelling of the hands, feet, ankles, or lower legs
• fever, infection
• nausea, vomiting, diarrhea
• extreme tiredness, loss of energy
• loss of appetite
• pain in the upper right part of the stomach
• yellowing of the skin or eyes
• flu-like symptoms

You should know that warfarin may cause necrosis or gangrene (death of skin or other body tissues). Call your doctor immediately if you notice dark or purple skin, ulcers, any unusual problem on your skin or body, sudden severe pain, or color or temperature change on your body. Call your doctor immediately if your toes hurt or turn purple or dark. You may need medical care right away to prevent amputation (removal) of your affected body part.

Warfarin may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.

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, moisture (not in the bathroom), and light.

Dispose of unneeded medications in a way so that pets, children, and other people cannot take them. Do not flush this medication down the toilet. Use a medicine take-back program. Talk to your pharmacist about take-back programs in your community. Visit the FDA's Safe Disposal of Medicines website https://goo.gl/c4Rm4p for more information.

Keep all medication out of sight and reach of children as many containers are not child resistant. Always lock safety caps. Place the medication in a safe location – one that is up and away and out of their sight and reach. https://www.upandaway.org

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at https://www.poisonhelp.org/help. If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911.

Symptoms of overdose may include the following:

• bloody or red, or tarry bowel movements
• spitting or coughing up blood
• heavy bleeding with your menstrual period
• pink, red, or dark brown urine
• coughing up or vomiting material that looks like coffee grounds
• small, flat, round red spots under the skin
• unusual bruising or bleeding
• continued oozing or bleeding from minor cuts

Carry an identification card or wear a bracelet stating that you take warfarin. Ask your pharmacist or doctor how to obtain this card or bracelet. List your name, medical problems, medications and dosages, and doctor's name and telephone number on the card.

Tell all your healthcare providers that you take warfarin.

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

Keep a written list of all of the prescription and nonprescription (over-the-counter) medicines, vitamins, minerals, and dietary supplements you are taking. Bring this list with you each time you visit a doctor or if you are admitted to the hospital. You should carry the list with you in case of emergencies.

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