From the Guidelines
Hydroxyurea is a highly effective treatment for patients with sickle cell disease, as it increases fetal hemoglobin production, reduces vaso-occlusive crises, and improves overall survival, with the most recent and highest quality study 1 demonstrating its benefits in reducing mortality and improving quality of life.
Mechanism of Action
Hydroxyurea works by mildly suppressing bone marrow production, leading to stress erythropoiesis that favors fetal hemoglobin (HbF) production, which inhibits the polymerization of hemoglobin S, reducing sickling and subsequent complications.
Dosage and Administration
The typical adult dose ranges from 15-35 mg/kg/day taken orally once daily, with treatment being lifelong for most patients.
Benefits
Hydroxyurea reduces painful vaso-occlusive crises by approximately 50%, decreases acute chest syndrome episodes, reduces blood transfusion requirements, and improves overall survival, as shown in studies 1.
Monitoring and Side Effects
Patients require regular blood monitoring (every 2-4 weeks initially, then every 2-3 months once stable) to check complete blood counts, reticulocytes, and liver/kidney function. Common side effects include mild bone marrow suppression, gastrointestinal symptoms, and skin changes.
Special Considerations
Hydroxyurea is contraindicated during pregnancy, so effective contraception is essential for women of childbearing potential. Maximum benefits typically appear after 3-6 months of consistent use. Some key points to consider when prescribing hydroxyurea include:
- Regular monitoring of blood counts and liver/kidney function
- Adjusting the dose based on patient response and side effects
- Counseling patients on the importance of consistent use and potential side effects
- Considering alternative treatments for patients who cannot tolerate hydroxyurea or have contraindications.
From the FDA Drug Label
The FDA drug label does not answer the question.
From the Research
How Hydroxyurea Helps Patients with Sickle Cell Disease
Hydroxyurea is a medication that has been shown to improve the clinical course of sickle cell disease (SCD) in some patients. The following are some ways in which hydroxyurea helps patients with SCD:
- Increases fetal hemoglobin (HbF) levels: Hydroxyurea has been shown to increase HbF levels in patients with SCD, which can help to reduce the frequency of painful crises and other complications of the disease 2, 3.
- Reduces frequency of painful crises: Studies have shown that hydroxyurea can reduce the frequency of painful crises in patients with SCD, with some patients experiencing a significant decrease in the number of crises per year 2, 4.
- Decreases hospitalization rates: Hydroxyurea has been shown to decrease hospitalization rates in patients with SCD, with some studies finding a significant reduction in the number of days spent in the hospital per year 5, 4.
- Improves hematologic parameters: Hydroxyurea has been shown to improve hematologic parameters, such as hemoglobin levels and mean corpuscular volume, in patients with SCD 5, 4.
Mechanism of Action
The exact mechanism of action of hydroxyurea in SCD is not fully understood, but it is thought to involve the increase in HbF levels, which can help to reduce the polymerization of sickle hemoglobin and decrease the frequency of painful crises 2, 3.
Side Effects and Toxicity
Hydroxyurea can cause side effects, such as myelosuppression, which can lead to a decrease in blood cell counts 5, 6. However, these side effects are generally reversible and can be managed with dose adjustments and monitoring of blood cell counts.
Patient Response to Hydroxyurea
Not all patients with SCD respond to hydroxyurea, and the response to treatment can vary widely between patients 3. Factors that may influence the response to hydroxyurea include the patient's baseline HbF level, the presence of certain genetic markers, and the patient's ability to tolerate the medication 3.