Hydroxyurea is used in sickle cell disease to do which of the following?

• A. Lower hemoglobin levels
• B. Increase white blood cell count
• C. Cure the disease
• D. Raise hemoglobin levels and decrease painful crises

Answer: (D)

Hydroxyurea works by increasing fetal hemoglobin (HbF) in red blood cells. HbF does not participate in the sickling process, so higher HbF reduces HbS polymerization when blood oxygen is low. Fewer polymerized HbS means fewer sickled cells and less vaso-occlusion, which translates into fewer painful crises and often an overall increase in hemoglobin levels because red cells survive longer. It’s a disease-modifying therapy, not a cure. It does not raise white blood cell counts; in fact, it can modestly suppress the marrow. So the statement that best matches its effect is that it raises hemoglobin levels and decreases painful crises.