Last update April 11, 2026

Relugolix

Compatible

Safe product and/or breastfeeding is the best option.

A gonadotropin-releasing hormone (GnRH) receptor antagonist used in the treatment of symptoms associated with uterine fibroids and endometriosis. It is administered orally, at a dose of 40 mg daily, usually in combination with oestradiol and norethisterone. 

According to a study conducted on 8 healthy breastfeeding mothers (Brimhall 2025), concentrations in breast milk are low and are not expected to cause adverse effects in infants.

Its low oral bioavailability (12%) makes it unlikely to pass into the infant’s plasma from ingested breast milk, except in preterm infants and during the immediate neonatal period, when intestinal permeability may be higher.

If a mother needs to take relugolix, this is not a reason to stop breastfeeding (LactMed); the infant should be monitored clinically for the onset of diarrhoea or other common side effects of the drug. (FDA 2024, AEMPS 2021)

As milk production depends on minimum levels of oestrogen, this product could theoretically reduce milk production.

 

 

 

 

 

 

 


See below the information of these related products:

  • Estradiol (Fairly safe. Mild or unlikely adverse effects. Compatible under certain circumstances. Follow-up recommended. Read Commentary.)
  • Norethisterone (Safe product and/or breastfeeding is the best option.)

Alternatives

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

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Group

Relugolix belongs to this group or family:

Tradenames

Main tradenames from several countries containing Relugolix in its composition:

  • Myfembree™. Contains other elements than Relugolix in its composition
  • Orgovyx™
  • Ryeqo™. Contains other elements than Relugolix in its composition

Pharmacokinetics

Variable Value Unit
Oral Bioavail. 12 %
Molecular weight 624 daltons
Protein Binding 68-71 %
pKa 9.07 -
Tmax 2.25 hours
T½ 25 - 61 hours
Theoretical Dose 0.0024 mg/Kg/d
Relative Dose 0.35 (0.25 - 0.5) %

References

  1. FDA. Relugolix. Drug Summary. 2025 Full text (in our servers)
  2. Brimhall DB, Chen YL, Lee S, Yoshida K, Ufer M. Transfer of the Oral Gonadotropin-Releasing Hormone Receptor Antagonist Relugolix Into Breast Milk of Healthy Lactating Women. Pharmacol Res Perspect. 2025 Feb;13(1):e70067. Abstract Full text (link to original source)
  3. Barretta M, Vignali M, La Marca A, Grandi G. The oral GnRH antagonists, a new class of drugs in gynecology: from pharmacokinetics to possible clinical applications. Expert Opin Drug Metab Toxicol. 2024 Dec 17:1-13. Abstract
  4. EMA. Relugolix. Ficha técnica. 2021 Full text (in our servers)

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