The Basics
What is Hydroxyurea?
Used by people with sickle cell anemia to reduce the number of painful crises caused by the disease and to reduce the need for blood transfusions.
Brand names for Hydroxyurea
Hydrea
How Hydroxyurea is classified
Antineoplastic Agents, Antisickling Agents, Enzyme Inhibitors, Nucleic Acid Synthesis Inhibitors
Hydroxyurea During Pregnancy
Hydroxyurea pregnancy category
Category N/ANote that the FDA has deprecated the use of pregnancy categories, so for some medications, this information isn’t available. We still think it’s useful to list historical info, however, given what a common proxy this has been in the past.
What we know about taking Hydroxyurea while pregnant
HYDREA can cause fetal harm based on findings from animal studies and the drug’s mechanism of action [see CLINICAL PHARMACOLOGY]. There are no data with HYDREA use in pregnant women to inform a drug-associated risk. In animal reproduction studies, administration of hydroxyurea to pregnant rats and rabbits during organogenesis produced embryotoxic and teratogenic effects at doses 0.8 times and 0.3 times, respectively, the maximum recommended human daily dose on a mg/m² basis (see Data). Advise women of the potential risk to a fetus and to avoid becoming pregnant while being treated with HYDREA. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2%-4% and 15%-20%, respectively.
Taking Hydroxyurea While Breastfeeding
What are recommendations for lactation if you're taking Hydroxyurea?
Most sources consider breastfeeding to be contraindicated during maternal antineoplastic drug therapy, although the evidence for this recommendation for hydroxyurea is very weak.[1][2] In doses used for sickle cell disease, hydroxyurea appears to be acceptable to use in nursing mothers. Avoiding breastfeeding for 3 hours after the mother’s dose can decrease the infant dose by about half. Chemotherapy may adversely affect the normal microbiome and chemical makeup of breastmilk.[3]
Maternal / infant drug levels
Most sources consider breastfeeding to be contraindicated during maternal antineoplastic drug therapy, although the evidence for this recommendation for hydroxyurea is very weak.[1][2] In doses used for sickle cell disease, hydroxyurea appears to be acceptable to use in nursing mothers. Avoiding breastfeeding for 3 hours after the mother’s dose can decrease the infant dose by about half. Chemotherapy may adversely affect the normal microbiome and chemical makeup of breastmilk.[3]
Possible effects of Hydroxyurea on milk supply
Relevant published information was not found as of the revision date.
Possible alternatives to Hydroxyurea
None listed
List of References
Lactation sources: Drugs and Lactation Database (LactMed) [Internet]. Bethesda (MD): National Library of Medicine (US); 2006-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK501922/1. Pistilli B, Bellettini G, Giovannetti E et al. Chemotherapy, targeted agents, antiemetics and growth-factors in human milk: How should we counsel cancer patients about breastfeeding? Cancer Treat Rev. 2013;39:207-11. PMID: 23199900
2. National Institutes of Health. National Heart Lung and Blood Institute. Evidence-based management of sickle cell disease. Expert panel report. 2014. http://www.nhlbi.nih.gov/sites/www.nhlbi.nih.gov/files/sickle-cell-disease-report.pdf
3. Urbaniak C, McMillan A, Angelini M et al. Effect of chemotherapy on the microbiota and metabolome of human milk, a case report. Microbiome. 2014;2:24. PMID: 25061513
4. Sylvester RK, Lobell M, Teresi ME et al. Excretion of hydroxyurea into milk. Cancer. 1987;60:2177-8. PMID: 3481556
5. Marahatta A, Ware RE. Hydroxyurea: Analytical techniques and quantitative analysis. Blood Cells Mol Dis. 2017;67:135-42. PMID: 28847416
6. Ware RE, Marahatta A, Ware JL et al. Hydroxyurea exposure in lactation-a pharmacokinetics study (HELPS). Blood. 2018;132 (Suppl 1):3677. Abstract. DOI: doi:10.1182/blood-2018-99-114142
Disclaimer: This material is provided for educational purposes only and is not intended for medical advice, diagnosis, or treatment. Consult your healthcare provider with any questions.
