Pharmacokinetics (PK) of Liquid Hydroxyurea in Pediatric Patients With Sickle Cell Anemia

Hydroxyurea (HU) is approved by the United States Food and Drug Administration (FDA) to treat adults with sickle cell anemia. Hydroxyurea has also been tested and used with children with sickle cell anemia. However, there are not many studies describing the disposition of drug in children less than 5 years old. The FDA has requested this study to better understand how children ages 2 to 17 years with sickle anemia absorb and eliminate the drug (this is called pharmacokinetics). The investigators will measure how much Hydroxyurea (HU) gets into the bloodstream at different time points after taking this medication.