Warfarin

This information from Lexicomp^® explains what you need to know about this medication, including what it’s used for, how to take it, its side effects, and when to call your healthcare provider.

Brand Names: US

Jantoven

Brand Names: Canada

APO-Warfarin; TARO-Warfarin

What is this drug used for?

• It is used to treat or prevent blood clots.
• It is used to lower the chance of heart attack, stroke, and death in some people.

What do I need to tell my doctor BEFORE I take this drug?

• If you are allergic to this drug; any part of this drug; or any other drugs, foods, or substances. Tell your doctor about the allergy and what signs you had.
• If you have any of these health problems: Blood vessel problems like, aneurysm or dissecting aorta; bleeding problems; bleeding in the brain; active ulcer; bleeding of the stomach, bowel, urinary tract, genitals, or respiratory tract; blood problems; heart infection; low platelet count; pericarditis, recent surgery of the eye, brain, or spine; or very high blood pressure.
• If you have any of these health problems: A certain health problem called pre-eclampsia, seizures during pregnancy (eclampsia), induction of labor, or threatened spontaneous abortion.
• If you are having surgery, talk with your doctor.
• If you will be getting spinal anesthesia or a spinal treatment.
• If you have had spinal anesthesia, surgery, or any spinal care, talk with your doctor.
• If you know that you will not take the drug or have your blood work (PT/INR) checked as you have been told.
• If you have a low platelet count caused by heparin.
• If you are pregnant.

This is not a list of all drugs or health problems that interact with this drug.

Tell your doctor and pharmacist about all of your drugs (prescription or OTC, natural products, vitamins) and health problems. You must check to make sure that it is safe for you to take this drug with all of your drugs and health problems. Do not start, stop, or change the dose of any drug without checking with your doctor.

What are some things I need to know or do while I take this drug?

• Tell all of your health care providers that you take this drug. This includes your doctors, nurses, pharmacists, and dentists. This drug may need to be stopped before certain types of surgery as your doctor has told you. If this drug is stopped, your doctor will tell you when to start taking this drug again after your surgery or procedure.
• Use care to prevent injury and avoid falls or crashes.
• If you fall or hurt yourself, or if you hit your head, call your doctor right away. Talk with your doctor even if you feel fine.
• You may bleed more easily. Be careful and avoid injury. Use a soft toothbrush and an electric razor.
• If you drink grapefruit juice or eat grapefruit often, talk with your doctor.
• Talk with your doctor before using products that have aspirin, blood thinners, garlic, ginseng, ginkgo, ibuprofen or like products, pain drugs, or vitamin E.
• Certain foods can affect your PT/INR levels. Follow the diet plan that your doctor or other health care provider told you about.
• Talk with your doctor about the amount of vitamin K in your diet. Vitamin K may change how this drug works. You do not have to avoid all foods with vitamin K. However, you will need to keep the amount of foods with vitamin K in your diet about the same from day to day. Many foods have vitamin K in them. This includes some green, leafy vegetables; broccoli; liver; and certain vegetable oils. Get a list of foods that have vitamin K in them from your doctor. Do not make big changes in your normal diet without talking with your doctor.
• Talk with your doctor before taking multivitamins, natural products, and diet aids. These may have vitamin K in them.
• Have patient safety card with you at all times.
• Call your doctor right away if you have diarrhea, a fever, or an infection.
• If you start or stop smoking, talk with your doctor. How much drug you take may need to be changed.
• A very bad and sometimes deadly health problem involving the skin (calciphylaxis) has happened with this drug. This has happened in people with and without very bad kidney problems. Talk with the doctor.
• If you are of Asian descent, use this drug with care. You could have more side effects.
• If you are 60 or older, use this drug with care. You could have more side effects.
• This drug may cause harm to an unborn baby. A pregnancy test will be done before you start this drug to show that you are NOT pregnant.
• If you may become pregnant, use birth control while taking this drug and for 1 month after your last dose. If you get pregnant, call your doctor right away.
• Tell your doctor if you are breast-feeding. You will need to talk about any risks to your baby.

What are some side effects that I need to call my doctor about right away?

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

• Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
• Weakness on 1 side of the body, trouble speaking or thinking, change in balance, drooping on one side of the face, or blurred eyesight.
• Chest pain.
• Severe dizziness or passing out.
• Swelling, warmth, numbness, change of color, or pain in a leg or arm.
• Very bad headache.
• Feeling very tired or weak.
• Swelling.
• Change in skin color to black or purple.
• Death of skin tissue may rarely happen. This can lead to loss of the body part (amputation) and can be deadly. Call your doctor right away if you have pain, color, or temperature change in any part of the body.
• If you have kidney problems or have had kidney problems in the past, talk with your doctor. Kidney problems may happen. Call your doctor right away if you have signs of kidney problems like not able to pass urine, change in how much urine is passed, blood in the urine, or a big weight gain.

What are some other side effects of this drug?

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if you have any side effects that bother you or do not go away.

These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.

You may report side effects to your national health agency.

You may report side effects to the FDA at 1-800-332-1088. You may also report side effects at https://www.fda.gov/medwatch.

How is this drug best taken?

Use this drug as ordered by your doctor. Read all information given to you. Follow all instructions closely.

• Use this drug exactly as you have been told, even if you feel well. This is important for the drug to work right and to lower the risk of bleeding.
• Take this drug at the same time of day.
• Pregnant people must not handle crushed or broken tablets. If a pregnant person touches a crushed or broken tablet, wash the area with soap and water right away.

What do I do if I miss a dose?

• Take a missed dose as soon as you think about it on the same day you missed the dose.
• If you do not think about the missed dose until the next day, skip the missed dose and go back to your normal time.
• Do not take more than 1 dose of this drug in the same day.

How do I store and/or throw out this drug?

• Store at room temperature protected from light. Store in a dry place. Do not store in a bathroom.
• Keep all drugs in a safe place. Keep all drugs out of the reach of children and pets.
• Throw away unused or expired drugs. Do not flush down a toilet or pour down a drain unless you are told to do so. Check with your pharmacist if you have questions about the best way to throw out drugs. There may be drug take-back programs in your area.

General drug facts

• If your symptoms or health problems do not get better or if they become worse, call your doctor.
• Do not share your drugs with others and do not take anyone else’s drugs.
• Some drugs may have another patient information leaflet. If you have any questions about this drug, please talk with your doctor, nurse, pharmacist, or other health care provider.
• This drug comes with an extra patient fact sheet called a Medication Guide. Read it with care. Read it again each time this drug is refilled. If you have any questions about this drug, please talk with the doctor, pharmacist, or other health care provider.
• If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.

Consumer Information Use and Disclaimer

This generalized information is a limited summary of diagnosis, treatment, and/or medication information. It is not meant to be comprehensive and should be used as a tool to help the user understand and/or assess potential diagnostic and treatment options. It does NOT include all information about conditions, treatments, medications, side effects, or risks that may apply to a specific patient. It is not intended to be medical advice or a substitute for the medical advice, diagnosis, or treatment of a health care provider based on the health care provider’s examination and assessment of a patient’s specific and unique circumstances. Patients must speak with a health care provider for complete information about their health, medical questions, and treatment options, including any risks or benefits regarding use of medications. This information does not endorse any treatments or medications as safe, effective, or approved for treating a specific patient. UpToDate, Inc. and its affiliates disclaim any warranty or liability relating to this information or the use thereof. The use of this information is governed by the Terms of Use, available at https://www.wolterskluwer.com/en/know/clinical-effectiveness-terms.

Last Reviewed Date

2023-07-14

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