Is Irinotecan safe while breastfeeding?
Here is what LactMed, the Drugs and Lactation Database published by the U.S. National Institute of Child Health and Human Development (NICHD), reports about Irinotecan. The text below is quoted from that source — it is not our own verdict.
Summary of use during breastfeeding
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.[1] Chemotherapy may adversely affect the normal microbiome and chemical makeup of breastmilk.[2] Women who receive chemotherapy during pregnancy are more likely to have difficulty nursing their infant.[3]
Effects on the breastfed infant
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.
Levels in milk
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.[1]
Infant Levels. Relevant published information was not found as of the revision date.
“No published information” means the studies do not exist yet — not that Irinotecan is known to be harmful, and not that it is known to be safe. Your prescriber or pharmacist can weigh your baby's age and whether a better-studied alternative would do the same job. Worth asking before stopping a medicine you need.
Source: Drugs and Lactation Database (LactMed), National Institute of Child Health and Human Development (NICHD), via NCBI Bookshelf, record “Irinotecan” (LM1290). LactMed on NCBI Bookshelf. LactMed is a registered trademark of the U.S. Department of Health and Human Services.
Educational summary of an authoritative source — not medical advice. Never start, stop, or change a medicine while breastfeeding without confirming with your doctor.