Is Fluorouracil safe while breastfeeding?
Here is what NIH LactMed, the U.S. National Library of Medicine's authority on medicines and breastfeeding, reports about Fluorouracil. This is a summary of that source — not our own verdict.
Effects on the breastfed infant
A woman was diagnosed with colorectal cancer at 26 weeks of gestation. She was treated with unspecified doses of fluorouracil, oxaliplatin, and calcium folinate (leucovorin calcium) at 28 weeks in the first of 3 planned doses. However, the infant was born at 30 weeks gestation, 14 days after the first dose. On day 1 postpartum, the infant was given colostrum mouth care and the mother s milk supply was initiated. On days 8 and 22 postpartum, the infusions of fluorouracil were given, without oxaliplatin. Pumped breastmilk was fed to the infant except for the 48 hours of fluorouracil infusion and for the 24 hours afterward. The infant was exclusively breastfed on discharged from the NICU on day 50 and at 11 months postpartum, the infant was thriving.[ 3 ]
Effects on milk supply
A telephone follow-up study was conducted on 74 women who received cancer chemotherapy at one center during the second or third trimester of pregnancy to determine if they were successful at breastfeeding postpartum. Only 34% of the women were able to exclusively breastfeed their infants, and 66% of the women reported experiencing breastfeeding difficulties. This was in comparison to a 91% breastfeeding success rate in 22 other mothers diagnosed during pregnancy, but not treated with chemotherapy. Other statistically significant correlations included: 1. mothers with breastfeeding difficulties had an average of 5.5 cycles of chemotherapy compared with 3.8 cycles among mothers who had no difficulties; and 2. mothers with breastfeeding difficulties received their first cycle of chemotherapy on average 3.4 weeks earlier in pregnancy. Of the 9 women who received a fluorouracil-containing regimen, 8 had breastfeeding difficulties.[ 5 ]
Levels in milk
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.[ 6 ] Infant Levels. Relevant published information was not found as of the revision date.
Source: NIH LactMed (National Library of Medicine).
Educational summary of an authoritative source — not medical advice. Never start, stop, or change a medicine while breastfeeding without confirming with your doctor.