Last update May 20, 2024

Prazosin Hydrochloride


Safe substance and/or breastfeeding is the best option.

An antihypertensive and antiadrenergic agent with peripheral action indicated in the treatment of hypertension and Raynaud's phenomenon. Oral administration in two daily doses.

According to the manufacturer, it is excreted in small amount in breast milk (Pfizer 2016 & 2009), with a relative dose of at most 3%. (Schaefer 2015, p 716)

Its pharmacokinetic data - large volume of distribution, high percentage of protein binding and short half-life (Pfizer 2016, Kirsten 1998)-, makes transfer into breastmilk in significant quantities unlikely.

Its low oral bioavailability hinders transfer to infant plasma from breastmilk, except in premature infants and the immediate neonatal period when there may be increased intestinal permeability.

It is structurally similar to doxazosin, which is excreted in breast milk in negligible amounts.

There is contradictory data regarding its action on prolactin, not affecting its levels according to some (Laakmann 1986, Barbieri 1980) or decreasing it according to others (Gumbatov 1992), but when breastfeeding is well established, milk production does not depend as much on levels of prolactin.(Messinis 1985).

Until there is more published data on this drug in relation to breastfeeding, safer known alternatives may be preferable (Anderson 2018, Malachias 2018, Schaefer 2007 p685), especially during the neonatal period and in cases of prematurity.


Suggestions made at e-lactancia are done by APILAM team of health professionals, and are based on updated scientific publications. It is not intended to replace the relationship you have with your doctor but to compound it. The pharmaceutical industry contraindicates breastfeeding, mistakenly and without scientific reasons, in most of the drug data sheets.

Jose Maria Paricio, Founder & President of APILAM/e-Lactancia

Your contribution is essential for this service to continue to exist. We need the generosity of people like you who believe in the benefits of breastfeeding.

Thank you for helping to protect and promote breastfeeding.

José María Paricio, founder of e-lactancia.

Other names

Prazosin Hydrochloride is also known as

Prazosin Hydrochloride in other languages or writings:


Main tradenames from several countries containing Prazosin Hydrochloride in its composition:


Variable Value Unit
Oral Bioavail. 40 - 68 %
Molecular weight 420 daltons
Protein Binding 95 %
VD 0.6 l/Kg
pKa 7.2 -
Tmax 3 hours
2 - 3 hours


  1. Anderson PO. Treating Hypertension During Breastfeeding. Breastfeed Med. 2018 Abstract
  2. Pfizer. Prazosina. Ficha técnica. 2016 Full text (in our servers)
  3. Malachias MV, Figueiredo CE, Sass N, Antonello IC, Torloni MR, Bortolotto MRF L. 7th Brazilian Guideline of Arterial Hypertension: Chapter 9 - Arterial Hypertension in pregnancy Arq Bras Cardiol. 2016 Abstract Full text (link to original source)
  4. Schaefer C, Peters P, Miller RK. Drugs During Pregnancy and Lactation. Treatment options and risk assessment. Elsevier, Third Edition. 2015
  5. Pfizer. Prazosin. Drug Summary. 2009 Full text (in our servers)
  6. Kirsten R, Nelson K, Kirsten D, Heintz B. Clinical pharmacokinetics of vasodilators. Part II. Clin Pharmacokinet. 1998 Abstract
  7. Gumbatov NB, Mustafaev II, Mamedova RN, Kasumova FZ, Karaev ME, Akhmedova ZG. [Effect of long-term treatment with prazosin and its combination with nadolol on the levels of blood hormones of the hypophyseal- gonadal system in patients with hypertension]. Kardiologiia. 1992 Abstract
  8. Laakmann G, Schoen HW, Zygan K, Weiss A, Wittmann M, Meissner R. Effects of receptor blockers (methysergide, propranolol, phentolamine, yohimbine and prazosin) on desimipramine-induced pituitary hormone stimulation in humans--II. Prolactin. Psychoneuroendocrinology. 1986 Abstract
  9. Messinis IE, Souvatzoglou A, Fais N, Lolis D. Histamine H1 receptor participation in the control of prolactin secretion in postpartum. J Endocrinol Invest. 1985 Apr;8(2):143-6. Abstract
  10. Barbieri C, Ferrari C, Borzio M, Piepoli V, Caldara R. Metabolic effects of chronic prazosin treatment. Horm Metab Res. 1980 Abstract

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