This study is about helping people with sickle cell disease who take a medicine called hydroxyurea (HU). Sickle cell disease is a condition where red blood cells become a sickle shape, causing pain and health issues. Hydroxyurea helps by increasing a type of hemoglobin called fetal hemoglobin (HbF) to reduce these problems. The study aims to find the best way to adjust the dose of hydroxyurea, so it works faster and better for patients.

Researchers want to see if a different method can make treatment more effective in less time. Instead of waiting 9-12 months, they think the new method could work in 6-9 months. This involves measuring how the body handles the drug to find the right dose quicker.

• Participation Length: Up to 15 months with regular visits every 3 months.
• Eligibility: People aged 2-35 with severe sickle cell disease in need of treatment adjustment.
• Risks and Benefits: Faster relief from symptoms, but potential side effects from dose changes.