Pharm
Hydroxyurea
search
Hydroxyurea
, Droxia, Hydrea, Hydroxycarbamide
Mechanism
Sickle Cell Anemia
Increases production of fetal
Hemoglobin
(HbF) which does not sickle
Indications
Malignancy
Polycythemia Vera
First-line agent indicated in high risk disease (history of thrombosis or age over 60 years old)
Chronic myelocytic
Leukemia
Head and Neck Squamous Cell Cancer
Melanoma
Sickle Cell Anemia
Indications in adults
Sickle Cell Crisis
3 or more times in 12 months
Severe or recurrent
Acute Chest Syndrome
Severe symptomatic chronic
Anemia
affecting functional status
Sickle cell associated pain significantly impacting function or quality of life
Indications in children over age 9 months
All children over age 9 months should be offered Hydroxyurea to reduce complications
Adverse Effects
Anemia
Neutropenia
Oral Ulcer
s
Skin Ulcer
s
Hyperpigmentation
Leukemogenicity risk in
Polycythemia Vera
(
Exercise
caution in age under 40 years old)
Leukemic transformation 0.4% persons per year
Myelofibrosis
5% at five years, 33.7% at 10 years
Ferrari (2019) Hematologica 104(12): 2391-9 [PubMed]
Contraindications
Pregnancy
Lactation
Monitoring
Sickle Cell Anemia
Baseline
Complete Blood Count
with differential
Reticulocyte Count
Hemoglobin F
quantitative measurement
Comprehensive metabolic panel (
Renal Function
tests,
Liver Function Test
s)
Pregnancy Test
Labs while adjusting dose (every 4 weeks or more)
Reticulocyte Count
Complete Blood Count
with differential and
Platelet
s
Maintain
Absolute Neutrophil Count
(ANC) > 2,000/mm3
Maintain
Platelet Count
>80,000/mm3
Labs when cytopenia occurs (every 1 week)
Reticulocyte Count
Complete Blood Count
with differential and
Platelet
s
Periodic labs when on stable dose (every 2-3 months)
Reticulocyte Count
Complete Blood Count
with differential and
Platelet
s
Hemoglobin F
quantitative measurement may be obtained to evaluate for response
Management
Sickle Cell Anemia
Often managed in conjunction with
Sickle Cell Disease
specialist
Trial for minimum of 6 months before assessing efficacy
Encourage compliance for maximal effect
Starting Doses
Obtain baseline labs as above prior to initiating Hydroxyurea
Arrange reliable
Contraception
for while on Hydroxyurea
Dosing: Infants and Children
Hydroxyurea 20 mg/kg daily
Dosing: Adults with normal
Renal Function
Hydroxyurea 15 mg/kg (round up to nearest 500 mg) daily
Dosing: Adults with
Chronic Kidney Disease
Hydroxyurea 5-10 mg/kg daily
Adjusting dose
See lab monitoring as above
Maximum daily dose: 35 mg/kg/day
Decreasing dose
Indications
Neutropenia
(ANC <2000/mm3)
Thrombocytopenia
(
Platelet Count
<80,000/mm3)
Approach
Consult with specialist
In some infants and children, ANC >1250/mm3 (instead of 2000/mm3) may be acceptable
Increase lab monitoring to weekly as above
Reduce Hydroxyurea dose by 5 mg/kg/day
Increasing dose
Target ANC 2000 to 4000/mm3
Increase by 5 mg/kg/day increments every 8 weeks
Efficacy
Sickle Cell Anemia
Full benefits may not be seen for the first 6 months after starting Hydroxyurea
Reduces
Sickle Cell Anemia
mortality and hospitalizations (fewer episodes of crisis and
Acute Chest Syndrome
)
Reduces
Sickle Cell Crisis
by 50%
Steinberg (2003) JAMA 289:1645-51 [PubMed]
Resources
NIH: NHLBI Evidence-Based Management of
Sickle Cell Disease
: Expert Panel Report, 2014
https://www.nhlbi.nih.gov/health-pro/guidelines/sickle-cell-disease-guidelines
References
Yawn (2015) Am Fam Physician 92(12): 1069-76 [PubMed]
Type your search phrase here