Last update Aug. 5, 2022


Low Risk

Possibly safe. Probably compatible. Mild risk possible. Follow up recommended. Read the Comment.

Sirolimus is a macrolide compound obtained from Streptomyces hygroscopicus with potent immunosuppressive properties. It is used to prevent organ transplant rejections, treat lymphangioleiomyomatosis, and perivascular epithelioid cell tumors. Oral or intravenous administration.

On latest update relevant data on breastfeeding was not found.

Its high molecular weight and plasma protein binding make excretion into breast milk unlikely.

Low oral biodisponibility would be protective for breastfed children who are not newborn or premature.

No problems were seen in one infant of a mother treated with sirolimus. (Braham 2013)

Until more published data is known about this drug in relation to breastfeeding, known safer alternatives are preferable (Constantinescu 2014), especially during the neonatal period and in the event of prematurity.


  • Azathioprine ( Safe. Compatible. Minimal risk for breastfeeding and infant.)
  • Tacrolimus ( Safe. Compatible. Minimal risk for breastfeeding and infant.)

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

Sirolimus in other languages or writings:

  • σιρόλιμος (Greek)
  • سيروليموس (Arabic)
  • Сиролимус (Cyrillic)
  • 西罗莫司 (Chinese)
  • シロリムス (Japanese)
  • (3S,6R,7E,9R,10R,12R,14S,15E,17E,19E,21S,23S,26R,27R,34aS)-9,10,12,13,14,21,22,23,24,25,26,27,32,33,34,34a-Hexadecahydro-9,27-dihydroxy-3-{(1R)-2-[(1S,3R,4R)-4-hydroxy-3-methoxycyclohexyl]-1-methylethyl}-10,21-dimethoxy-6,8,12,14,20,26-hexamethyl-23,27-epoxy-3H-pyrido[2,1-c][1,4]oxaazacyclohentriacontine-1,5,11,28,29(4H,6H,31H)-pentone (Chemical name)
  • C51H79NO13 (Molecular formula)
  •  L04AA10; S01XA23 (ATC Code/s)


Sirolimus belongs to these groups or families:


Main tradenames from several countries containing Sirolimus in its composition:


Variable Value Unit
Oral Bioavail. 14 %
Molecular weight 914 daltons
Protein Binding 92 %
VD 0.17 ± 0.1 l/Kg
pKa 9.96 -
Tmax 2.1 - 3.5 hours
62 ± 16 hours


  1. Constantinescu S, Pai A, Coscia LA, Davison JM, Moritz MJ, Armenti VT. Breast-feeding after transplantation. Best Pract Res Clin Obstet Gynaecol. 2014 Nov;28(8):1163-73. Abstract
  2. Bramham K, Chusney G, Lee J, Lightstone L, Nelson-Piercy C. Breastfeeding and tacrolimus: serial monitoring in breast-fed and bottle-fed infants. Clin J Am Soc Nephrol. 2013 Abstract
  3. Sirolimus Ficha técnica 2011 Full text (in our servers)
  4. Sirolimus Drug Summary 2011 Full text (in our servers)

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