Can you take idursulfase 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 idursulfase during breastfeeding. Because it is a large protein molecule with a molecular weight of about 76,000 Da, the amount in milk is likely to be very low and absorption is unlikely because it is probably destroyed in the infant's gastrointestinal tract. If idursulfase is required by the mother, it is not a reason to discontinue breastfeeding. Until more data are available, idursulfase should be used with infant careful monitoring during breastfeeding.
Quoted from Idursulfase — Drugs and Lactation Database (LactMed®), National Institute of Child Health and Human Development, revised April 15, 2026.
How much idursulfase 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 idursulfase while breastfeeding?
No information is available on the clinical use of idursulfase 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 idursulfase pass into breastmilk?
LactMed's measured drug levels for idursulfase are quoted in full on this page, under "How much gets into breastmilk".
Do I need to pump and dump after taking idursulfase?
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 idursulfase
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.