Hydroxyurea: Modifier of pathophysiology in sickle cell anemia

Sickle cell anemia (SCA) patients have a point mutation in the 6th codon of the hemoglobin gene in which adenine is replaced by thymine resulting in replacement of glutamic acid with valine on the 6th amino acid in the β globin chain of the hemoglobin. Despite identical basic genetic mutation in all SCA patients, significant variation in clinical severity occurs. Clinical severity of SCA varies from mild to very severe types requiring more intensive medical interventions such as use of hydroxyurea (HU) and stem cell transplantation. Use of HU has improved clinical outcome in SCA and is recommended for moderate-to-severe varieties of SCA. This review brings to the fore mode of action, indications, commencement of therapy, monitoring, toxicity, and discontinuation of HU in selected SCA patients.