Sickle Cell Disease and Hydroxyurea

What is sickle cell disease?

Sickle cell disease is a genetic disorder that affects red blood cells. Red blood cells carry oxygen to all parts of the body. Normal red blood cells are donut shaped and travel through blood vessels easily. Sickle cell disease causes red blood cells to become stiff and crescent shaped (“sickled”). Sickled red blood cells are fragile and have a shorter life span than normal red blood cells. As the body cannot replace the red blood cells fast enough, a person with sickle cell disease has a reduced number of these cells (anemia). When the red blood cells sickle, they can clog blood vessels and cause pain and organ damage.

What is hydroxyurea?

Hydroxyurea is a prescription medicine taken by mouth. In sickle cell disease, it is used to:

• reduce the number and severity of painful events
• prevent acute chest syndrome (sudden onset of difficult breathing)
• reduce the need for blood transfusions
• decrease hospital stays
• improve life expectancy
• decrease the risk of organ damage

How does hydroxyurea work?

Hydroxyurea raises the amount of fetal hemoglobin (HbF) in red blood cells. HbF is a type of hemoglobin that usually goes away during the first year of life. HbF helps keep red blood cells from sickling.

Hydroxyurea also lowers the number of white blood cells and platelets. White blood cells and platelets are often high in patients with sickle cell disease. Too many white blood cells and platelets can cause damage to the blood vessels, as well as lead to complications such as strokes and acute chest syndrome.

Hydroxyurea does not work right away. It can take several months for the hydroxyurea to start to work. It must be taken EVERY DAY.

Common side effects of hydroxyurea:

• Lowers white blood cells - increased risk of infection if too low
• Lowers platelets - increased risk of bleeding if platelets are too low
• Discolored nails
• Weight gain or weight loss
• Skin rash
• Hair thinning
• Nausea
• Diarrhea or constipation

We will follow your child closely while on hydroxyurea to look for these side effects. Side effects can generally be reversed with dose changes. If you notice any of the above side effects or you are concerned about your child, contact the sickle cell office at (757) 668-8260 or (757) 668-7243.

Call your child’s doctor immediately if your child has an allergic reaction such as hives, itching, difficulty breathing, chest tightness, swelling of the face, lips, or tongue.

Other facts about hydroxyurea:

It is necessary to monitor blood counts regularly when taking hydroxyurea. Low blood counts are usually managed by lowering dose or stopping the medication for a few weeks.

Avoid pregnancy while taking hydroxyurea. This medicine may cause harm to an unborn baby if it is taken while pregnant. If you become pregnant, stop hydroxyurea immediately and contact your doctor’s office right away.