From the Guidelines
Patients taking hydroxyurea should be monitored with a complete blood count (CBC) and reticulocyte count every 1 to 3 months, depending on the duration of treatment and stability of the dose. This monitoring is crucial to detect potential adverse effects of hydroxyurea, particularly myelosuppression, which can lead to serious complications 1.
Key Monitoring Parameters
- Complete blood count (CBC) with differential, including white blood cell count, hemoglobin, hematocrit, platelet count, and absolute neutrophil count (ANC)
- Reticulocyte count
Monitoring Frequency
The frequency of monitoring may vary depending on the individual patient's response to hydroxyurea and the duration of treatment. Generally, more frequent monitoring is required when initiating therapy or adjusting the dose 1.
Additional Considerations
While the provided evidence does not extensively discuss vital signs monitoring, in clinical practice, it is essential to monitor vital signs, including blood pressure, heart rate, respiratory rate, and temperature, at each clinical visit to promptly identify any potential issues.
Special Considerations
Special attention should be paid to signs of myelosuppression, and dose adjustment or discontinuation may be necessary if significant cytopenias are detected 1.
From the FDA Drug Label
Monitor blood counts at least once a week during hydroxyurea therapy. Evaluate hematologic status prior to and during treatment with hydroxyurea capsules. Close monitoring of hematologic parameters is advised in these patients.
The patient taking hydroxyurea should be monitored for:
- Blood counts at least once a week
- Hematologic status prior to and during treatment
- Hematologic parameters (especially in patients with renal impairment) Additionally, the patient should be monitored for signs of:
- Myelosuppression
- Hemolytic anemia
- Cutaneous vasculitis 2
From the Research
Laboratory Tests to Monitor
- Complete Blood Count (CBC) to monitor for signs of bone marrow suppression, such as pancytopaenia, as reported in a case study 3
- Liver function tests to monitor for elevations in liver enzyme function tests, as seen in a patient who experienced acute elevations in liver function tests after starting hydroxyurea 4
- Renal function tests to monitor for signs of renal impairment, as hydroxyurea pharmacokinetics are influenced by renal function 5
Vital Signs to Monitor
- Temperature to monitor for signs of infection, such as fever, which can be a side effect of hydroxyurea 4
- Blood pressure to monitor for signs of cardiovascular complications, although there is limited evidence on the long-term risks of hydroxyurea 6
Additional Monitoring
- Monitor for signs of acute chest syndrome, blood transfusions, and infections, as these can be affected by hydroxyurea treatment 6
- Monitor for neurological events, such as stroke, in patients with sickle cell anaemia at risk of primary stroke 6
- Monitor for adverse events, including serious or life-threatening events, although the evidence on these is limited 6