Lanzkron and colleagues synthesized the evidence on the efficacy, effectiveness, and toxicity of hydroxyurea for treating
adults with sickle cell disease. They found that hydroxyurea increases fetal hemoglobin in adults with sickle cell disease
and reduces the frequency of pain crises, hospital-days, and transfusions. They found far less evidence on hydroxyurea's effect
on hospitalization, stroke, pain crises, the acute chest syndrome, and death outcomes. Limited evidence indicated that hydroxyurea
treatment of sickle cell disease is not associated with leukemia or leg ulcers. The evidence was insufficient to estimate
the risk for skin neoplasms.