Is Ivacaftor safe while breastfeeding?
Here is what NIH LactMed, the U.S. National Library of Medicine's authority on medicines and breastfeeding, reports about Ivacaftor. This is a summary of that source — not our own verdict.
Effects on the breastfed infant
A woman with cystic fibrosis was treated with lumacaftor and ivacaftor during pregnancy and postpartum. Her infant was fully breastfed until day 29 postpartum when direct and indirect bilirubin, aspartate aminotransferase (AST), and alkaline phosphatase were found to be elevated. All values had been normal on days 1 and 14. The proportion of breastmilk the infant received was reduced to 25% and all values were normal on day 37. The fraction of breastfeeding was increased to 50% and then to 100%. On day 135, the infant's direct bilirubin was elevated during concurrent maternal levofloxacin and trimethoprim-sulfamethoxazole therapy. The fraction of breastfeeding was decreased to 75% and the direct bilirubin was normal on day 154. The authors noted that the abnormal test results could not definitively be attributed to lumacaftor and ivacaftor therapy.[ 3 ] A survey was sent to lead clinicians of adult CF centers in Europe, the United Kingdom, United States of America, Australia and Israel requesting anonymized data on pregnancy outcomes in women using CFTR modulators during pregnancy and lactation. Responses were received from 31 centers and one woman with CF for a total of 64 pregnancies in 61 women resulting in 60 live births. Thirteen infants were breastfed on ivacaftor alone, 9 infants were breastfed on lumacaftor and ivacaftor, and 5 infants were breastfed on tezacaftor and ivacaftor for a total of 27 infants exposed to ivacaftor in breastmilk, all with no reported complications. The extent of breastfeeding was not reported.[ 4 ] An updated survey by the same authors asked CF clinicians to report on pregnant women exposed to the elexacaftor, tezacaftor and ivacaftor combination during pregnancy and breastfeeding. Twenty-six infants were breastfed (extent not stated) during maternal use of the combination. No adverse effects were reported in the breastfed infants.[ 5 ] An infant was born to a mother taking elexacaftor, ivacaftor and tezacaftor for cystic fibrosis.
Effects on milk supply
Relevant published information was not found as of the revision date.
Levels in milk
Additional information on the concentrations of ivacaftor in maternal milk and infant serum can be found in the record on Elexacaftor, Tezacaftor, and Ivacaftor . Maternal Levels. A woman with cystic fibrosis was treated with lumacaftor and ivacaftor during pregnancy and postpartum. The dosage was not stated, but it was probably the standard dosage of lumacaftor 400 mg and ivacaftor 250 mg orally every 12 hours. The average concentration of ivacaftor in breastmilk samples taken randomly over a 6-month period without regard to the times of the doses was 35.3 mcg/L (0.09 micromolar).[ 3 ] Infant Levels. An infant was breastfed by a mother taking lumacaftor and ivacaftor. The percentage of breastfeeding varied between 25% and 100% during this time period. The average infant ivacaftor plasma concentration over the first 6 months of life, excluding day 1 postpartum, was 3.9 mcg/L (0.01 micromolar). This value corresponded to average of 0.5% of simultaneous maternal plasma levels.[ 3 ]
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.