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Droxia Dosage

Generic name: hydroxyurea 300mg
Dosage form: capsule
Drug class: Antimetabolites

Medically reviewed by Last updated on Mar 6, 2023.

Dosing Information

Table 1: Dosing Recommendation Based on Blood Count

Dosing Regimen


Dose Modification Criteria

Monitoring Parameters

Initial Recommended

15 mg/kg/day as a single dose once daily based on the patient’s actual or ideal weight, whichever is less.

Monitor the patient’s blood count every 2 weeks [see Warnings and Precautions (5.1)].

Dosing Based on
Blood Counts

In an acceptable

Increase dose
5 mg/kg/day every 12 weeks

Maximal dose:
35 mg/kg/day*

*Maximal dose is the highest dose that does not produce toxic blood counts over 24 consecutive weeks.

Increase dosing only if blood counts are in an acceptable range.

Do not increase if myelosuppression occurs.

Blood Counts Acceptable Range

neutrophils ≥2500 cells/mm3

platelets ≥95,000/mm3

hemoglobin >5.3 g/dL

reticulocytes ≥95,000/mm3 if
the hemoglobin
concentration <9 g/dL

Between acceptable
and toxic range

Do not increase dose.

If blood counts are considered toxic, discontinue DROXIA until hematologic recovery.

Blood Counts Toxic Range

neutrophils <2000 cells/mm3

platelets <80,000/mm3

hemoglobin <4.5 g/dL

reticulocytes <80,000/mm3 if
the hemoglobin
concentration <9 g/dL

Dosing After

Reduce dose by
2.5 mg/kg/day.

Reduce the dose from the dose associated with hematologic toxicity.

May titrate up or down every 12 weeks in 2.5 mg/kg/day increments.

The patient should be at a stable dose with no hematologic toxicity for 24 weeks.

Discontinue the treatment permanently if a patient develops hematologic toxicity twice.

Swallow DROXIA capsules whole. Do NOT open, break, or chew capsules because DROXIA is a cytotoxic drug. Patients must be able to follow directions regarding drug administration and their monitoring and care.

Fetal hemoglobin (HbF) levels may be used to evaluate the efficacy of DROXIA in clinical use. Obtain HbF levels every three to four months. Monitor for an increase in HbF of at least two-fold over the baseline value.

DROXIA causes macrocytosis, which may mask the incidental development of folic acid deficiency. Prophylactic administration of folic acid is recommended.

DROXIA is a cytotoxic drug. Follow applicable special handling and disposal procedures [see References (15)].

Dose Modifications for Renal Impairment

Reduce the dose of DROXIA by 50% in patients with creatinine clearance of less than 60 mL/min or with end-stage renal disease (ESRD) [see Use in Specific Populations (8.6) and Clinical Pharmacology (12.3)]. Creatinine clearance values were obtained using 24-hour urine collections.

* On dialysis days, administer DROXIA to patients with ESRD following hemodialysis.

Creatinine Clearance


Recommended DROXIA Initial Dose

(mg/kg once daily)



<60 or ESRD*


Monitor the hematologic parameters closely in these patients.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.