Is Capecitabine 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 Capecitabine. The text below is quoted from that source — it is not our own verdict.
Summary of use during breastfeeding
Most sources consider breastfeeding to be contraindicated during maternal antineoplastic drug therapy.[1] It might be possible to breastfeed safely during intermittent therapy with an appropriate period of breastfeeding abstinence. some have suggested a period of 24 hours before resuming nursing,[2] although the manufacturer recommends an abstinence period of 2 weeks. Capecitabine is metabolized to fluorouracil. Limited information indicates that a maternal continuous intravenous fluorouracil infusion at a dose of 200 mg/square meter daily produces undetectable levels in milk. If capecitabine use is undertaken, monitoring of the infant's complete blood count and differential is advisable. Chemotherapy may adversely affect the normal microbiome and chemical makeup of breastmilk.[3] Women who receive chemotherapy during pregnancy are more likely to have difficulty nursing their infant.[4]
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
Capecitabine is a prodrug that is metabolized to fluorouracil.
Maternal Levels. A mother who was 9 months postpartum was diagnosed with rectal cancer and began treatment with pelvic radiotherapy and a continuous intravenous infusion of fluorouracil 200 mg/square meter daily. Her plasma fluorouracil concentration was constant at about 110 micromoles/L (14.3 mg/L) from weeks 2 to 5 of therapy. She discontinued nursing her infant and pumped her breasts twice daily and collected 36 breastmilk samples before, during and for 10 days following fluorouracil therapy (exact times not specified). Fluorouracil was undetectable (<0.5 micromole/L [<65 mcg/L]) in all of the milk samples.[5]
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 Capecitabine 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 “Capecitabine” (LM1296). 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.