NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.

Drugs and Lactation Database (LactMed) [Internet]. Bethesda (MD): National Library of Medicine (US); 2006-.

Cover of Drugs and Lactation Database (LactMed)

Drugs and Lactation Database (LactMed) [Internet].

Show details


Last Revision: December 15, 2019.

Estimated reading time: 2 minutes

CASRN: 143090-92-0

Drug Levels and Effects

Summary of Use during Lactation

Anainra is the pharmaceutical name for recombinant human interleukin-1 receptor antagonist (IL-1Ra). IL-1Ra is a normal component of human milk where it may play a role as an anti-inflammatory agent. No data exist on the excretion of anakinra into breastmilk after exogenous administration. Several infants have been breastfed during maternal anakinra therapy with no obvious adverse effects. If anakinra is required by the mother, it is not a reason to discontinue breastfeeding.[1]

Drug Levels

Maternal Levels. The concentration of IL-1Ra in colostrum in normal mothers was 672 ng/L, which was higher than the plasma concentration. Mature milk levels were lower than those in colostrum. Samples collected over a period of 2 to 6 months postpartum indicated that mothers continued to excrete IL-1Ra during this time.[2] Mothers with acute mastitis had slightly higher average levels of IL-1Ra than levels after recovery, but the median values were the same. The levels found in these mothers were the same as those of control mothers.[3]

Infant Levels. Relevant published information was not found as of the revision date.

Effects in Breastfed Infants

A woman was receiving anakinra 100 mg daily for adult-onset Still's disease during pregnancy and lactation. Her breastfed (extent not stated) infant gained wight and appeared to have normal psychomotor development during an unspecified follow-up period.[4]

Among a cohort of 18 women with term pregnancies treated with anakinra for cryopyrin-associated periodic syndromes during pregnancy, 3 of the women breastfed their infants (extent not stated) for periods of <1 month, 3 months and 1 year. No adverse neonatal outcomes were reported.[5]

In an international multicenter study of mothers exposed to interleukin-1 receptor antagonists, 10 babies were breastfed (extent not stated) by mothers receiving anakinra for up to 10 months. No infections or developmental abnormalities were reported.[6] Three of the cases had been reported previously in reference[5].

Of 5 women who took anakinra during pregnancy, two breastfed their infants while continuing to receive anakinra 100 mg daily. No serious infections were reported and development was normal.[7]

Effects on Lactation and Breastmilk

Relevant published information was not found as of the revision date.


Gotestam Skorpen C, Hoeltzenbein M, Tincani A, et al. The EULAR points to consider for use of antirheumatic drugs before pregnancy, and during pregnancy and lactation. Ann Rheum Dis. 2016;75:795–810. [PubMed: 26888948]
Buescher ES, Malinowska I. Soluble receptors and cytokine antagonists in human milk. Pediatr Res. 1996;40:839–44. [PubMed: 8947960]
Buescher ES, Hair PS. Human milk anti-inflammatory component contents during acute mastitis. Cell Immunol. 2001;210:87–95. [PubMed: 11520075]
Berger CT, Recher M, Steiner U, Hauser TM. A patient's wish: anakinra in pregnancy. Ann Rheum Dis. 2009;68:1794–5. [PubMed: 19822718]
Chang Z, Spong CY, Jesus AA, et al. Anakinra use during pregnancy in patients with cryopyrin-associated periodic syndromes (CAPS). Arthritis Rheumatol. 2014;66:3227–32. [PMC free article: PMC4323990] [PubMed: 25223501]
Youngstein T, Hoffmann P, Gul A, et al. International multi-centre study of pregnancy outcomes with interleukin-1 inhibitors. Rheumatology (Oxford). 2017;56:2102–8. [PMC free article: PMC6251516] [PubMed: 28968868]
Smith CJF, Chambers CD. Five successful pregnancies with antenatal anakinra exposure. Rheumatology (Oxford). 2018;57:1271–5. [PubMed: 29660063]

Substance Identification

Substance Name


CAS Registry Number


Drug Class

Breast Feeding


Antirheumatic Agents


Disclaimer: Information presented in this database is not meant as a substitute for professional judgment. You should consult your healthcare provider for breastfeeding advice related to your particular situation. The U.S. government does not warrant or assume any liability or responsibility for the accuracy or completeness of the information on this Site.


Related information

  • PMC
    PubMed Central citations
  • PubMed
    Links to PubMed

Similar articles in PubMed

See reviews...See all...

Recent Activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...