How to manage hydroxyurea in sickle cell disease patients requiring blood transfusion?

Management of Hydroxyurea in Sickle Cell Disease Patients Requiring Blood Transfusion

Hydroxyurea therapy should be temporarily discontinued when sickle cell disease patients require blood transfusion, and can be safely resumed 24-48 hours after transfusion once hemoglobin levels have stabilized. 1

Pre-Transfusion Considerations

• For patients on hydroxyurea who require transfusion, the decision should be guided by the transfusion indication and baseline hemoglobin levels 2
• Patients with sickle cell disease on chronic hydroxyurea who are also on long-term transfusion programs (e.g., for stroke prevention) should maintain their HbS percentage below 30% 2
• For patients with HbSS/HbSβ0 genotypes with baseline Hb <90 g/L, a top-up transfusion aiming for Hb of 100 g/L is recommended 2
• For patients with HbSS/HbSβ0 genotypes with baseline Hb ≥90 g/L, a partial exchange transfusion aiming for Hb of 100 g/L is preferred 2

Hydroxyurea Management During Transfusion

• Temporarily hold hydroxyurea administration on the day of transfusion and for 24-48 hours afterward to prevent potential myelosuppressive effects 1
• Monitor complete blood counts weekly following transfusion while on hydroxyurea therapy to assess for potential myelosuppression 3
• The target post-transfusion hemoglobin should not exceed 100 g/L to avoid hyperviscosity, especially in patients on hydroxyurea 2
• Hemoglobin should not be increased by more than 40 g/L in a single transfusion episode for patients on hydroxyurea 2

Post-Transfusion Resumption of Hydroxyurea

• Resume hydroxyurea therapy 24-48 hours after transfusion once hemoglobin levels have stabilized 1
• For patients with chronic kidney disease and worsening anemia, combination therapy with hydroxyurea and erythropoiesis-stimulating agents may be considered after transfusion and stabilization 4
• When using combination therapy, maintain hemoglobin levels below 10 g/L to reduce the risk of vaso-occlusive complications 1
• Reduce the dose of hydroxyurea when administered to patients with creatinine clearance <60 mL/min or with end-stage renal disease following hemodialysis 3

Special Considerations

• For patients who are difficult to transfuse due to multiple antibodies, hydroxyurea can be used to optimize pre-operative hemoglobin and reduce the chance of sickling 2
• In patients who refuse blood transfusion (e.g., Jehovah's Witnesses), pre-operative erythropoiesis-stimulating agents or hydroxyurea may be appropriate to optimize hemoglobin levels 2
• For patients on hydroxyurea who develop acute chest syndrome despite elevated HbF levels, transfusion should not be delayed, and hydroxyurea can be resumed after stabilization 2, 5
• Patients on hydroxyurea who require exchange transfusion for stroke prevention should not discontinue transfusion therapy based on elevated HbF levels alone, as this may increase stroke risk 2

Monitoring Parameters

• Monitor plasma and urine hydroxyurea levels when available to assess treatment efficacy and compliance after transfusion 6
• Track mean corpuscular volume (MCV) changes before and after transfusion, as plasma hydroxyurea concentrations positively correlate with MCV increases 6
• Regular monitoring of neutrophil counts is essential when resuming hydroxyurea after transfusion, as myelosuppression is a common side effect 7
• For patients receiving both hydroxyurea and transfusion therapy, careful monitoring for potential adverse effects including iron overload is necessary 8