Can you take cobimetinib 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.
No information is available on the clinical use of cobimetinib during breastfeeding. Because cobimetinib is 90% bound to plasma proteins, the amount in milk is likely to be low. However, its half-life is about 44 hours, and it might accumulate in the infant. The manufacturer recommends that breastfeeding be discontinued during cobimetinib therapy and for 2 weeks after the last dose.
Quoted from Cobimetinib — Drugs and Lactation Database (LactMed®), National Institute of Child Health and Human Development, revised July 15, 2025.
How much cobimetinib gets into breastmilk
Maternal Levels. Relevant published information was not found as of the revision date.
Infant Levels. Relevant published information was not found as of the revision date.
What has been seen in breastfed infants
Relevant published information was not found as of the revision date.
Effects on milk supply
Relevant published information was not found as of the revision date.
Frequently asked questions
Can you take cobimetinib while breastfeeding?
No information is available on the clinical use of cobimetinib during breastfeeding. 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.
Does cobimetinib pass into breastmilk?
LactMed's measured drug levels for cobimetinib are quoted in full on this page, under "How much gets into breastmilk".
Do I need to pump and dump after taking cobimetinib?
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 cobimetinib
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.