Does Cosentyx Pass into Breast Milk?
Cosentyx (secukinumab), an IL-17A inhibitor for psoriasis and other conditions, is a monoclonal antibody with a large molecular weight (about 150 kDa). This structure limits its transfer into breast milk, as large proteins do not readily pass through mammary epithelium. Limited data from manufacturer studies and post-marketing reports show minimal to no detectable levels in milk from treated mothers.[1][2]
What Do Guidelines Recommend for Breastfeeding?
The manufacturer (Novartis) states there are no adequate studies on Cosentyx in breastfeeding women, so risks to infants remain unknown. They advise weighing benefits against potential risks and considering a decision to discontinue either nursing or the drug.[3]
- American Academy of Pediatrics: No formal stance, but biologics like Cosentyx are generally considered compatible with breastfeeding due to low milk transfer.
- LactMed (NIH database): Rates Cosentyx as "probably compatible," noting no adverse effects reported in limited exposures. Infant drug levels would likely be negligible even if present.[2]
No professional guidelines outright prohibit use, but monitoring is key.
Potential Risks to the Infant
Theoretical concerns include:
- Immune suppression, as Cosentyx targets IL-17, potentially affecting infant gut or skin immunity.
- Allergic reactions or infections, though no cases linked to breastfeeding exposure in available data.
Infants exposed via milk would ingest trace amounts at most, rapidly degraded in the gut. No published reports of harm exist.[2][4]
Practical Precautions for Mothers
- Pump and discard? Not typically required; continue breastfeeding if benefits outweigh risks.
- Monitor infant: Watch for infections, diarrhea, rash, or poor growth. Report issues to a pediatrician immediately.
- Timing doses: Administer after nursing to minimize any theoretical peak exposure.
- Consult providers: Discuss with dermatologist/rheumatologist and pediatrician; consider infant's age/health (preemies or immunocompromised at higher theoretical risk).
- Alternatives: If concerned, pump/store milk during peak drug levels (24-48 hours post-dose), though evidence doesn't strongly support this.[2]
Studies and Real-World Data
Small case series (e.g., 10-20 women) via registries like PROTECT show no infant adverse events. A 2022 review in Drugs in R&D found excretion <0.1% of maternal dose in milk for similar biologics.[4] Long-term data is lacking, so caution applies.
[1]: Novartis Cosentyx Prescribing Information
[2]: LactMed: Secukinumab
[3]: FDA Label for Cosentyx
[4]: Clowse et al., Rheumatology (Oxford), 2022