Last update Sept. 20, 2023

Allopregnanolone. Allotetrahydroprogesterone


Safe substance and/or breastfeeding is the best option.

Progesterone metabolite, GABA-A receptor modulator, used in the treatment of postpartum depression.

Administration in continuous intravenous infusion for 60 hours.

It is excreted in human milk in clinically insignificant amount. (Wald 2022, FDA 2019, Hoffmann 2019)

Its very low oral bioavailability makes it difficult to pass into infant plasma from ingested breast milk.

No problems have been observed in infants whose mothers it was given. (FDA 2019)

It can cause excessive sedation and loss of consciousness during its administration, so the mother must be monitored and attended.(FDA 2019)

It is not recommended to share a bed with the baby or remain unattended while breastfeeding during the administration of the product.


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

Allopregnanolone. Allotetrahydroprogesterone is also known as Brexanolone.

Allopregnanolone. Allotetrahydroprogesterone in other languages or writings:


Allopregnanolone. Allotetrahydroprogesterone belongs to this group or family:


Main tradenames from several countries containing Allopregnanolone. Allotetrahydroprogesterone in its composition:


Variable Value Unit
Oral Bioavail. <5% %
Molecular weight 319 daltons
Protein Binding 99 %
VD 3 l/Kg
pKa 18.3 -
9 hours
M/P ratio 1.36 -
Theoretical Dose < 0.0015 mg/Kg/d
Relative Dose 0.7 - 2 %


  1. Wald J, Henningsson A, Hanze E, Hoffmann E, Li H, Colquhoun H, Deligiannidis KM. Allopregnanolone Concentrations in Breast Milk and Plasma from Healthy Volunteers Receiving Brexanolone Injection, With Population Pharmacokinetic Modeling of Potential Relative Infant Dose. Clin Pharmacokinet. 2022 Sep;61(9):1307-1319. Abstract Full text (link to original source)
  2. FDA. Brexanolone (Zulresso). Drug Summary. 2019 Full text (in our servers)
  3. Hoffmann E, Wald J, Dray D, Colquhoun H. Brexanolone injection administration to lactating women: Breast milk allopregnanolone levels. Obstet Gynecol. 2019;133 Suppl 1:115S–Abstract 30J. Abstract
  4. Hoffmann E, Wald J, Colquhoun H. Evaluation of breast milk concentrations following brexanolone iv administration to healthy lactating women. Am J Obstet Gynecol 2019;220:S554. Abstract 850. doi:10.1016/j.ajog.2018.11.873. Abstract

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