The Role of Hydroxyurea in Reducing Vaso-occlusive Complications in Adults with Sickle Cell Disease: A Review of the Evidence

Abstract

Introduction: Sickle cell disease (SCD) is a chronic, inherited blood disorder characterized by recurrent, painful vaso-occlusive crises (VOCs) and cumulative end-organ damage. Historically, management was primarily supportive. Hydroxyurea emerged as a promising disease-modifying therapy aimed at ameliorating the underlying pathophysiology.

Literature Review: A review of the pivotal clinical literature establishes hydroxyurea as the cornerstone of preventive therapy for adults with severe SCD. Its primary mechanism of action is the induction of protective fetal hemoglobin (HbF), which dilutes the concentration of sickle hemoglobin and inhibits the polymerization process that causes red cell sickling. The long-term follow-up of a landmark randomized controlled trial provided definitive evidence of sustained efficacy. This research demonstrated that long-term hydroxyurea therapy significantly reduces the frequency of VOCs, the incidence of the life-threatening acute chest syndrome, and the need for blood transfusions. This sustained clinical benefit was associated with a significant reduction in mortality. Subsequent research also identified additional beneficial mechanisms, including anti-inflammatory effects and improved blood flow.

Conclusion: The body of evidence confirms that hydroxyurea is a safe and effective disease-modifying agent for adults with severe sickle cell disease. Its proven ability to decrease the rate of acute, painful, and life-threatening complications has transformed the management of SCD from a reactive, crisis-focused approach to a proactive, preventative standard of care.