Pediatric Medication

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

Coumadin [DSC]; Jantoven

Brand Names: Canada

APO-Warfarin; Coumadin [DSC]; TARO-Warfarin


  • This drug may cause very bad and sometimes deadly bleeding. Talk with the doctor.
  • Call the doctor right away if your child has any signs of bleeding problems, like bruising; black, tarry, or bloody stools; bleeding gums; blood in the urine; coughing up blood; cuts that take a long time to stop bleeding; feeling dizzy; feeling very tired or weak; nosebleeds; pain or swelling; throwing up blood or throw up that looks like coffee grounds; or very bad headache.
  • Call the doctor right away if your child has vaginal bleeding that is not normal or very heavy periods (menstrual bleeding).
  • You will need to have your child’s blood work (PT/INR) checked while your child takes this drug. This is important to make sure the drug works right and to check your child’s risk of bleeding. Have your child’s PT/INR checked as you have been told by your child’s doctor or other health care provider. If you are not sure when you need to have your child’s PT/INR checked, call your child’s doctor or other health care provider.
  • Your child’s diet and certain drugs may affect your child’s PT/INR level. Talk with the doctor.
  • Have your child avoid actions or sports that may raise the chance of injury.

What is this drug used for?

  • It is used to treat blood clots.
  • It is used to thin the blood so that clots will not form.
  • It is used to lower the chance of heart attack, stroke, and death in some people.

What do I need to tell the doctor BEFORE my child takes this drug?

  • If your child is allergic to this drug; any part of this drug; or any other drugs, foods, or substances. Tell the doctor about the allergy and what signs your child had.
  • If your child has 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 your child is pregnant or may be pregnant.
  • If your child is having surgery, talk with the doctor.
  • Tell the doctor your child uses this drug before your child gets spinal anesthesia or a spinal treatment.
  • If your child has had spinal anesthesia, surgery, or any spinal care, talk with your child’s doctor.
  • If you know that your child will not take the drug or have blood work (PT/INR) checked as you have been told by the doctor.
  • If your child has a low platelet count caused by heparin.

If your child is pregnant:

  • If your child has any of these health problems: A certain health problem called pre-eclampsia, seizures during pregnancy (eclampsia), induction of labor, or threatened spontaneous abortion.

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

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

What are some things I need to know or do while my child takes this drug?

  • Tell all of your child’s health care providers that your child is taking this drug. This includes your child’s doctors, nurses, pharmacists, and dentists. This drug may need to be stopped before certain types of surgery as the doctor has told you. If this drug is stopped, the doctor will tell you when to start giving this drug again after your child’s surgery or procedure.
  • Use care to prevent your child from getting hurt and have your child avoid falls or crashes.
  • If your child falls, gets hurt, or hits their head, call the doctor right away. Talk with the doctor even if your child feels fine.
  • Your child may bleed more easily. Make sure your child is careful and avoids injury. Be sure your child has a soft toothbrush.
  • If your child drinks grapefruit juice or eats grapefruit often, talk with your child’s doctor.
  • Talk with the doctor before giving your child products that have aspirin, blood thinners, garlic, ginseng, ginkgo, ibuprofen or like products, pain drugs, or vitamin E.
  • Certain foods can affect your child’s PT/INR levels. Have your child follow the diet plan your child’s doctor or other health care provider told you about.
  • Talk with the doctor about the amount of vitamin K in your child’s diet. Vitamin K may change how this drug works. Your child does not have to avoid all foods with vitamin K. However, you will need to keep the amount of foods with vitamin K in your child’s 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 child’s doctor. Do not make big changes in your child’s normal diet without talking with the doctor.
  • Talk to your child’s doctor before giving your child multivitamins, natural products, and diet aids. These may have vitamin K in them.
  • Have your child’s patient safety card with you at all times.
  • Call the doctor right away if your child has diarrhea, a fever, or an infection.
  • If your child stops or starts smoking, talk with the doctor. How much drug your child takes may need to be changed.
  • If your child is of Asian descent, use this drug with care. Your child could have more side effects.
  • 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 your child is of childbearing age, a pregnancy test will need to be done before starting this drug to make sure your child is not pregnant.

If your child is or may be sexually active:

  • This drug may cause harm to the unborn baby if your child takes it during pregnancy.
  • Have your child use birth control while taking this drug and for some time after the last dose. Ask the doctor how long your child must use birth control. If your child becomes pregnant, call the doctor right away.

If your child is breast-feeding a baby:

  • Tell the doctor if your child is breast-feeding a baby. You will need to talk about any risks to the baby.

What are some side effects that I need to call my child’s 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 child’s doctor or get medical help right away if your child has 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.
  • Very bad 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 the doctor right away if your child has pain, color, or temperature change in any part of the body.
  • If your child has kidney problems or has had kidney problems in the past, talk with your child’s doctor. Kidney problems may happen. Call your child’s doctor right away if your child has 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 child’s doctor or get medical help if your child has any side effects that bother your child 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 child’s doctor. Call your child’s doctor for medical advice about side effects.

You may report side effects to your national health agency.

How is this drug best given?

Give this drug as ordered by your child’s doctor. Read all information given to you. Follow all instructions closely.

  • Give this drug exactly as you have been told, even if your child feels well. This is important for the drug to work right and to lower the risk of bleeding.
  • Give this drug at the same time of day.
  • Pregnant people must not handle crushed or broken tablets.

What do I do if my child misses a dose?

  • Give a missed dose as soon as you think about it on the same day your child missed the dose.
  • If it is the next day, skip the missed dose and go back to your child’s normal time.
  • Do not give 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 child’s symptoms or health problems do not get better or if they become worse, call your child’s doctor.
  • Do not share your child’s drug with others and do not give anyone else’s drug to your child.
  • Some drugs may have another patient information leaflet. If you have any questions about this drug, please talk with your child’s doctor, nurse, 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 information should not be used to decide whether or not to take this medicine or any other medicine. Only the healthcare provider has the knowledge and training to decide which medicines are right for a specific patient. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about this medicine. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this medicine. This information is not specific medical advice and does not replace information you receive from the healthcare provider. You must talk with the healthcare provider for complete information about the risks and benefits of using this medicine. The use of this information is governed by the Lexicomp End User License Agreement, available at https://www.wolterskluwer.com/en/solutions/lexicomp/about/eula.

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