Limited information indicates that maternal doses of 4 mg daily produce low very levels in milk and would not be expected to cause any adverse effects in breastfed infants.
Drug Levels
Maternal Levels. A woman who was nursing a 6-month-old infant received 2 doses of doxazosin 4 mg 24 hours apart. Four milk samples were obtained after the second dose. A peak milk level of 4.2 mcg/L occurred at 1 hour after the dose. The average concentration over the 18-hour study period was 2.9 mcg/L. The authors estimated that a fully breastfed infant would receive an average daily dosage of 440 ng/kg daily or about 0.6% of the maternal weight-adjusted dosage.[1]
A woman with pheochromocytoma during pregnancy was treated near term with doxazosin and metoprolol. She continued doxazosin for 3 days postpartum until adrenal surgery. Thirty hours after her last dose of 8 mg of doxazosin, the drug was undetectable (<25 mcg/L) in her breastmilk.[2]
Infant Levels. Relevant published information was not found as of the revision date.
Effects in Breastfed Infants
Relevant published information was not found as of the revision date.
Effects on Lactation and Breastmilk
Relevant published information in nursing mothers was not found as of the revision date. However, the pharmacologically similar drug prazosin does not affect serum prolactin concentration in patients with hypertension,[3,4] indicating that doxazosin may not affect prolactin levels. The prolactin level in a mother with established lactation may not affect her ability to breastfeed.
References
1.
Jensen BP, Dalrymple JM, Begg EJ. Transfer of doxazosin into breast milk. J Hum Lact 2013;29:150-3. (corrected in J Hum Lact 2014;30: NP3-NP4). PMID: 23439864. [PubMed: 23439864]
2.
Versmissen J, Koch BC, Roofthooft DW, et al. Doxazosin treatment of phaeochromocytoma during pregnancy: Placental transfer and disposition in breast milk. Br J Clin Pharmacol. 2016;82:568–9. [PMC free article: PMC4972176] [PubMed: 27194370]
3.
Barbieri C, Caldara R, Ferrari C, et al. Metabolic effects of prazosin. Clin Pharmacol Ther. 1980;27:313–6. [PubMed: 6102000]
4.
Barbieri C, Ferrari C, Borzio M, et al. Metabolic effects of chronic prazosin treatment. Horm Metab Res. 1980;12:331–4. [PubMed: 6105121]
Substance Identification
Substance Name
Doxazosin
CAS Registry Number
74191-85-8
Drug Class
Breast Feeding
Lactation
Adrenergic alpha-Antagonists
Antihypertensive Agents
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