Can you take irinotecan 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.
Limited data indicate that irinotecan is found in breastmilk for 2 days and its active metabolite is found in breastmilk for up to a week after a dose of 60 mg/square meter, although the highest amounts occur during the first 4 days after a dose. Higher maternal doses have not been studied and the oral absorption and toxicity in breastfed infants are not known. Based on this limited evidence, it appears that breastfeeding should be avoided for at least a week after a dose of irinotecan 60 mg/square meter. Higher dosages probably require a longer abstinence period. Some authors recommend discontinuing breastfeeding during irinotecan therapy. Chemotherapy may adversely affect the normal microbiome and chemical makeup of breastmilk. Women who receive chemotherapy during pregnancy are more likely to have difficulty nursing their infant.
Quoted from Irinotecan — Drugs and Lactation Database (LactMed®), National Institute of Child Health and Human Development, revised January 15, 2025.
How much irinotecan gets into breastmilk
Irinotecan is metabolized to the active metabolite, 7-ethyl-10-hydroxycamptothecin (SN-38), which is further conjugated with glucuronic acid.
Maternal Levels. A woman with cervical cancer discovered during pregnancy was treated with irinotecan 60 mg/square meter plus nedaplatin 80 mg/square meter. She had been nursing her infant prior to chemotherapy and collected morning breastmilk samples on days 2 to 7 following the first dose of irinotecan. Irinotecan was detectable in breastmilk on days 2 and 3 after the dose in concentrations of 399 and 60.21 mcg/L, respectively. Irinotecan was undetectable (<0.1 mcg/L) on day 4 and after. SN-38 was also measured, but not its glucuronide. SN-38 was highest in breastmilk on day 2, with a concentration of 3.9 mcg/L. Levels fell, but were still measurable on days 6 and 7, with concentrations of 0.16 and 0.2 mcg/L, respectively.
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 irinotecan while breastfeeding?
What the NIH's Drugs and Lactation Database says about Irinotecan while breastfeeding — quoted in full. 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 irinotecan pass into breastmilk?
LactMed's measured drug levels for irinotecan are quoted in full on this page, under "How much gets into breastmilk".
Do I need to pump and dump after taking irinotecan?
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 irinotecan
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.