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Hydroxyurea Dosage

Medically reviewed on June 20, 2018.

Applies to the following strengths: 500 mg; 200 mg; 300 mg; 400 mg; 1000 mg; 100 mg

Usual Adult Dose for Chronic Myelogenous Leukemia

15 mg/kg/day orally as a single dose

Comments:
-NOTE: Different products have different approved indications. Consult the manufacturer product information for approved indications.
-Therapy should be individualized based on tumor type, disease state, response to treatment, patient risk factors, and current clinical practice standards.
-All dosages should be based on patient actual or ideal weight, whichever is less.
-Prophylactic administration of folic acid is recommended.
-Blood counts should be monitored at least once a week during therapy.
-Severe anemia should be corrected before initiating therapy.

Uses:
-Resistant chronic myeloid leukemia (CML)
-Locally advanced squamous cell carcinomas of the head and neck (excluding lip), in combination with concurrent chemoradiation

Usual Adult Dose for Head and Neck Cancer

15 mg/kg/day orally as a single dose

Comments:
-NOTE: Different products have different approved indications. Consult the manufacturer product information for approved indications.
-Therapy should be individualized based on tumor type, disease state, response to treatment, patient risk factors, and current clinical practice standards.
-All dosages should be based on patient actual or ideal weight, whichever is less.
-Prophylactic administration of folic acid is recommended.
-Blood counts should be monitored at least once a week during therapy.
-Severe anemia should be corrected before initiating therapy.

Uses:
-Resistant chronic myeloid leukemia (CML)
-Locally advanced squamous cell carcinomas of the head and neck (excluding lip), in combination with concurrent chemoradiation

Usual Adult Dose for Sickle Cell Anemia

15 mg/kg orally once a day; increase 5 mg/kg/day every 12 weeks
Maximum dose: 35 mg/kg/day

Dosing based on blood counts:
-Counts in acceptable range: Increase dose 5 mg/kg/day every 12 weeks to a maximum dose of 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 acceptable range; do not increase if myelosuppression occurs.
-Counts between acceptable and toxic range: Do not increase dose; if in toxic range, discontinue therapy until hematologic recovery.
-Dosing after hematologic recovery: 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 treatment permanently if patient develops hematologic toxicity twice.

BLOOD COUNTS IN THE ACCEPTABLE RANGE:
-Neutrophils greater than or equal to 2500 cells/mm3
-Platelets greater than or equal to 95,000/mm3
-Hemoglobin greater than 5.3 g/dL
-Reticulocytes greater than or equal to 95,000/mm3 if the hemoglobin concentration is less than 9 g/dL
BLOOD COUNTS IN THE TOXIC RANGE:
-Neutrophils less than 2000 cells/mm3
-Platelets less than 80,000/mm3
-Hemoglobin less than 4.5 g/dL
-Reticulocytes less than 80,000/mm3 if the hemoglobin concentration is less than 9 g/dL

DOSING AFTER HEMATOLOGIC RECOVERY:
-Reduce the 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 therapy permanently if the patient develops hematologic toxicity twice.

Comments:
-NOTE: Different products have different approved indications. Consult the manufacturer product information for approved indications.
-Dosage is based on the actual or ideal patient weight, whichever is less.
-The patient blood count should be monitored every 2 weeks.
-Fetal hemoglobin (HbF) levels may be used to evaluate the efficacy of therapy in clinical use. Obtain HbF levels every 3 to 4 months. Monitor for an increase in HbF of at least 2-fold over the baseline value.
-Prophylactic administration of folic acid is recommended.

Use: To reduce the frequency of painful crises and to reduce the need for blood transfusions in patients with sickle cell anemia with recurrent moderate to severe painful crises.

Usual Pediatric Dose for Sickle Cell Anemia

2 years and older:
20 mg/kg orally once a day; increase 5 mg/kg/day every 8 weeks or if a painful crisis occurs; increase dosing only if blood counts are in the acceptable range; do not increase dosing if myelosuppression occurs; if blood counts are considered toxic, discontinue therapy until hematologic recovery
Duration of therapy: Give until mild myelosuppression (absolute neutrophil count 2000/microliter to 4000/microliter) is achieved, up to 35 mg/kg/day
Maximum dose: 35 mg/kg/day

BLOOD COUNTS IN THE ACCEPTABLE RANGE:
-Neutrophils greater than or equal to 2000 cells/mm3
-Platelets greater than or equal to 80,000/mm3
-Hemoglobin greater than 5.3 g/dL
-Reticulocytes greater than or equal to 80,000/mm3 if the hemoglobin concentration is less than 9 g/dL
BLOOD COUNTS IN THE TOXIC RANGE:
-Neutrophils less than 2000 cells/mm3
-Platelets less than 80,000/mm3; younger patients with lower baseline counts may safely tolerate absolute neutrophil counts down to 1250/mm3
-Hemoglobin less than 4.5 g/dL
-Reticulocytes less than 80,000/mm3 if the hemoglobin concentration is less than 9 g/dL

DOSING AFTER HEMATOLOGIC RECOVERY:
-Reduce the dose by 5 mg/kg/day.
-Reduce the dose from the dose associated with hematologic toxicity.
-May titrate up or down every 8 weeks in 5 mg/kg/day increments.
-The patient should be at a stable dose with no hematologic toxicity for 24 weeks.
-Discontinue therapy permanently if the patient develops hematologic toxicity twice.

Comments:
-NOTE: Different products have different approved indications. Consult the manufacturer product information for approved indications.
-Dosage is based on the actual or ideal patient weight, whichever is less.
-The patient blood count should be monitored every 2 weeks.
-Fetal hemoglobin (HbF) levels may be used to evaluate the efficacy of therapy in clinical use. Obtain HbF levels every 3 to 4 months. Monitor for an increase in HbF of at least 2-fold over the baseline value.
-Prophylactic administration of folic acid is recommended.

Use: To reduce the frequency of painful crises and to reduce the need for blood transfusions in pediatric patients, 2 years of age and older, with sickle cell anemia with recurrent moderate to severe painful crises

Renal Dose Adjustments

-CrCl 60 mL/minute or greater: Initial dose: 15 mg/kg/day
-CrCl less than 60 mL/minute or end stage renal disease (ESRD): Initial dose: 7.5 mg/kg/day OR reduce the dose by 50%

Liver Dose Adjustments

Data not available; however, caution is recommended.

Dose Adjustments

-Concurrent use of this drug with other myelosuppressive agents may require adjustment of dosages.
-Although no specific dose adjustment guidelines have been suggested, elderly patients may require a lower dose of this drug.

Precautions

US BOXED WARNINGS:
-MYELOSUPPRESSION: This drug may cause severe myelosuppression. Blood counts should be monitored at baseline and throughout therapy. Therapy should be interrupted and the dose should be reduced as necessary.
-MALIGNANCIES: This drug is carcinogenic. Patients should use sun protection and be monitored for malignancies.

Safety and efficacy have not been established in patients younger than 2 years for sickle cell anemia. Safety and efficacy have not been established in patients younger than 18 years for all other indications.

Consult WARNINGS section for additional precautions.

Dialysis

Hemodialysis: Administer the dose following hemodialysis.

Other Comments

Administration advice:
-All dosage should be based on the patient's actual or ideal weight, whichever is less.
-The contents of capsules may be emptied into a glass of water and administered immediately. The contents of the capsule should not be inhaled or allowed to come into contact with the skin or mucous membranes.

General:
-Different individual products are used for specific indications. The manufacturer product information should be consulted prior to using a product.

Further information

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

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