How do we treat blood clots in children?


  • Anticoagulants: The term your health care team members use to refer to medications that treat blood clots. Most people outside the medical field call them “blood thinners” or anti-clotting medication. These medications don’t really thin the blood. They just make it harder for your blood to clot.
  • Heparin “drip”: A type of blood thinner or anti-clotting medication we give nonstop through an IV or flexible tube directly into your child’s vein
  • Low-molecular-weight heparin: A type of anti-clotting medication or blood thinner we give by a shot under the skin about every 12 hours.
  • Warfarin: An anti-clotting medication or blood thinner that patients take in pill form. In the United States, you may hear it called by the brand name Coumadin®.
  • INR test: A blood test that measures clotting levels in the blood of patients who take warfarin
  • Thrombolysis: Clot-buster therapy. We give clot-buster therapy in different ways. Most clots do not require this kind of treatment.

When doctors diagnose your child with blood clots for the first time, they will usually treat your child with blood thinners.

  • Blood thinners decrease the risk of getting more blood clots. They also help prevent life-threatening PEs or lung clots.

  • No one has proven that blood thinner can “get rid of” blood clots.

  • Doctors and scientists do not yet understand the factors that lead blood clots to resolve over time. One factor may include how well your child’s own body “breaks down” a clot.

  • We usually start to treat children’s blood clots with blood thinners while they are still in the hospital.

  • Most often, we either start children on a heparin “drip” through an IV, or with “low- molecular-weight heparin” shots. We give low-molecular-weight heparin shots under the skins about every 12 hours.

  • Before they go home, doctors usually switch children over to low-molecular-weight heparin shots for home use. Your child’s doctor may also switch your child to a once-a-day blood thinner pill called warfarin or Coumadin® in the U.S.

  • If your child can’t swallow pills, you can crush warfarin and give it to your child mixed with certain liquids. A children’s pharmacist can give you instructions.

  • Diet and other medicines can affect warfarin’s ability to control your blood clotting. Because of this, warfarin requires weekly to monthly blood tests to check clotting levels in your child’s blood. We call this an “INR” test. The INR test requires a blood sample drawn from a vein, usually on the inside of the elbow.

  • The federal government has approved other blood thinner pills beside warfarin to treat blood clots in adults. Scientists continue to study these newer blood thinners to check their safety and effectiveness in children.

  • In some severe cases of blood clots, doctors may recommend clot-buster therapy – called thrombolysis. Clot busting therapy removes or breaks up your child’s blood clot soon after the doctor diagnoses it. After children finish clot-busting treatment, they will take other more common blood thinners, like low-molecular-weight heparin or warfarin.

  • In addition to treatment with blood thinners, you and your doctor must address the blood clot risk factors that may have caused your child’s blood clot. This helps prevent new blood clots. For example:

    • Your doctor will prescribe antibiotics to treat severe bacterial infections that may have caused the blood clot;

    • Your doctor will stop or remove birth control pills, patches and rings that can cause blood clot.

    • Your doctor will also remove “central line” catheters when no longer needed.

Neil A. Goldenberg, MD, PhD

Associate Professor of Pediatrics and Medicine, Johns Hopkins University School of Medicine,
Baltimore, MD, USA

Chief Research Officer and Director, Thrombosis Program,
All Children’s Hospital Johns Hopkins Medicine and All Children’s Research Institute,
St. Petersburg, FL, USA     March 2014

Download: Blood Clots and Children Resource PDF

Blood Clots in Children

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