Can you take sarilumab while breastfeeding?
What LactMed says
The National Library of Medicine’s own summary, quoted in full. We do not write a verdict of our own on this question, and we do not compress theirs into a label.
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. It is also likely to be partially destroyed in the infant's gastrointestinal tract and absorption by the infant is probably minimal. 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. 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.
Quoted from Sarilumab — Drugs and Lactation Database (LactMed®), National Institute of Child Health and Human Development, revised May 15, 2025.
What LactMed would consider instead
LactMed ends this record by naming the drugs it would consider in place of sarilumab. Whether any of them fits depends on what you are treating — this is the database’s list, not a recommendation from us.
How much sarilumab gets into breastmilk
Maternal Levels. A lactating woman was receiving subcutaneous sarilumab 150 mg every 2 weeks for rheumatoid arthritis. After 5 doses of the drug, she donated 6 milk samples over a 28-day period. The peak concentration of about 160 mcg/L occurred on day 3 after the dose. By day 7, the milk sarilumab concentration decreased to about 110 mcg/L; on day 14, the milk concentration was about 75 mcg/L. The drug was undetectable in mill at 28 days after the dose.
Infant Levels. Relevant published information was not found as of the revision date.
What has been seen 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.
Effects on milk supply
Relevant published information was not found as of the revision date.
Frequently asked questions
Can you take sarilumab while breastfeeding?
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. The full record is quoted on this page, and the decision is one to make with the person who prescribed it — LactMed itself states it is not a substitute for professional judgement.
What can I take instead of sarilumab while breastfeeding?
LactMed lists Adalimumab, Certolizumab Pegol, Etanercept, Infliximab, Tocilizumab as alternate drugs to consider. That is the database's own list for this drug — whether any of them suits you depends on what you are treating.
Does sarilumab pass into breastmilk?
LactMed's measured drug levels for sarilumab are quoted in full on this page, under "How much gets into breastmilk".
Do I need to pump and dump after taking sarilumab?
LactMed does not frame its records that way — it reports measured drug levels in milk and what has been observed in breastfed infants, which is what this page quotes. "Pump and dump" advice for a specific drug and dose should come from your clinician or a pharmacist, not from a general rule.
More on sarilumab
LactMed states that the information it presents is not a substitute for professional judgement, and that you should consult your healthcare provider for breastfeeding advice related to your particular situation. Nothing on this page is medical advice.