What is hydroxyurea?

Hydroxyurea is a medicine that can help children and adults with sickle cell disease.

Research studies show that hydroxyurea lowers the following:

  1. The numbers of acute chest syndrome (pneumonia) events
  2. The number of pain crises
  3. The need for blood transfusions
  4. The number of trips to the hospital
  5. Hydroxyurea also might prevent damage to the spleen, kidneys, lungs, and brain.
Hydroxyurea is given by mouth one (1) time each day. It comes in a capsule form. The U.S. Food and Drug Administration (FDA) has approved it for the treatment of adults and children with severe sickle cell disease. Numerous medical centers have carried out research studies to learn more about giving hydroxyurea safely and effectively to children with sickle cell disease.

Which children should take hydroxyurea?

We consider hydroxyurea for children with sickle cell disease who have had:
  • Many painful events.
  • Several cases of acute chest syndrome (pneumonia).
  • Severe anemia
  • Other special problems with their internal organs.

Children with SS and S Beta Zero variants may start on hydroxyurea prophylactically by the age of 9-12 months.

How does hydroxyurea work?

Red blood cells contain hemoglobin. Hemoglobin helps red blood cells carry oxygen from the lungs to other parts of the body. People with normal hemoglobin have mostly Hemoglobin A in their red blood cells. People with sickle cell disease have mostly sickle or Hemoglobin S (Hb S) in their red blood cells.

Hb S is an abnormal type of hemoglobin. In people with sickle cell disease, Hb S causes the red blood cells to change from a round shape to a sickle or banana shape. Also, Hb S causes the red blood cells to become rigid and sticky. This leads to blockage of blood flow to important body organs, muscles, and tissues.

Hydroxyurea treatment helps the red blood cells stay round and flexible. This lets them travel more easily through tiny blood vessels. In part, this happens because hydroxyurea increases the amount of fetal hemoglobin (Hb F) in red blood cells. Newborn babies have Hb F when they are born. Hb F helps protect them from sickle cell complications (health problems) during the first few months of life. With an increased amount of Hb F, red blood cells are less likely to change into the sickle or banana shape. In most people, the amount of Hb F decreases after the first few months of life. Some people have more Hb F than others. People with sickle cell disease who have higher levels of Hb F usually have fewer complications of the disease.


Reviewed by: Athena Pefkarou, MD

This page was last updated on: 1/29/2019 3:21:13 PM

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