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Sarilumab use while Breastfeeding

Medically reviewed by Last updated on Dec 7, 2023.

Drugs containing Sarilumab: Kevzara

Sarilumab Levels and Effects while Breastfeeding

Summary of Use during Lactation

Because sarilumab is a large protein molecule with a molecular weight of about 150,000 Da, the amount in milk is likely to be very low.[1] It is also likely to be partially destroyed in the infant's gastrointestinal tract and absorption by the infant is probably minimal.[2] One infant was safely breastfed for 6 months after maternal sarilumab was resumed at 28 days postpartum. If sarilumab is required by the mother, it is not a reason to discontinue breastfeeding.[3] Until more data become available, sarilumab should be used with caution during breastfeeding, especially while nursing a newborn or preterm infant. Waiting for at least 2 weeks postpartum to resume therapy may minimize transfer to the infant.[4]

Drug Levels

Maternal Levels. A lactating woman was receiving subcutaneous sarilumab 150 mg every 2 weeks for rheumatoid arthritis. At 20 days postpartum after having received 5 doses of the drug, she donated 4 samples of milk over a 7-day period. The peak concentration of about 200 mcg/L occurred on day 3 after the dose. By day 7, the milk sarilumab concentration decreased to about 100 mcg/L.[5]

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

Effects in Breastfed Infants

A woman with rheumatoid arthritis refractory to etanercept took sarilumab 200 mg every two weeks during pregnancy until 37 weeks of gestation. She was also taking prednisolone 10 mg and tacrolimus 3 mg daily. She delivered a healthy infant at 38 weeks of gestation and breastfed her infant. Prednisolone was continued postpartum; tacrolimus was restarted at 7 days postpartum and sarilumab was restarted at 28 days postpartum. The mother continued to breastfeed until 6 months postpartum. The infant was vaccinated with multiple live vaccines after reaching six months old, including the Bacille-Calmette-Guerin vaccine, with no adverse effects.[6]

Effects on Lactation and Breastmilk

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

Alternate Drugs to Consider

(Rheumatoid Arthritis) Adalimumab, Certolizumab Pegol, Etanercept, Infliximab, Tocilizumab


Stratigakis A, Paty D, Zou P, et al. A regression approach for assessing large molecular drug concentration in breast milk. Reprod Breed 2023;3:199-207. doi:10.1016/j.repbre.2023.10.003 [CrossRef]
Anderson PO. Monoclonal antibodies during breastfeeding. Breastfeed Med 2021;16:591-3. [PubMed: 33956488]
Götestam 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]
Krysko KM, Dobson R, Alroughani R, et al. Family planning considerations in people with multiple sclerosis. Lancet Neurol 2023;22:350-66. [PubMed: 36931808]
Saito J, Yakuwa N, Hosokawa Y, et al. Establishment of a measurement system to evaluate breast milk transfer of biological agents using dry filter paper: a multi-institutional study. Br J Clin Pharmacol 2023. [PubMed: 37548054]
Mizutani S, Okunishi Y, Tamada T, et al. A woman with rheumatoid arthritis who successfully delivered a healthy child with continuous administration of sarilumab throughout pregnancy. Intern Med 2023;62:633-6. [PMC free article: PMC10017234] [PubMed: 35871593]

Substance Identification

Substance Name


CAS Registry Number


Drug Class

Breast Feeding


Milk, Human

Antibodies, Monoclonal

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.

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