Benefit should outweigh risk

AU TGA pregnancy category: B3
US FDA pregnancy category: Not assigned

Risk Summary: There is limited and incomplete data on use of this drug in pregnant women; studies in rats and rabbits have demonstrated no teratogenicity or adverse effects on fetal development at doses that produced maternal exposures up to approximately 5 (rats) and 11 (rabbits) times exposure at maximum recommended human doses (MRHD).

Comments:
-Due to limited experience, this drug should be used only if clearly needed and the expected benefit to the mother justifies the potential risks to the fetus.

Animal studies have failed to reveal evidence of teratogenicity at doses up to 11 times the MRHD. Decreased fetal body weight was observed at a maternally toxic dose (5 times the MRHD). Placental transfer has been observed in pregnant rats and rabbits. There are no controlled data in human pregnancy.

AU TGA pregnancy category B3: Drugs which have been taken by only a limited number of pregnant women and women of childbearing age, without an increase in the frequency of malformation or other direct or indirect harmful effects on the human fetus having been observed. Studies in animals have shown evidence of an increased occurrence of fetal damage, the significance of which is considered uncertain in humans.

US FDA pregnancy category Not Assigned: The US FDA has amended the pregnancy labeling rule for prescription drug products to require labeling that includes a summary of risk, a discussion of the data supporting that summary, and relevant information to help health care providers make prescribing decisions and counsel women about the use of drugs during pregnancy. Pregnancy categories A, B, C, D and X are being phased out.

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Lacteal excretion of this drug was observed following a single radiolabel oral dose administered 9 to 10 days postpartum to lactating rats. Exposure was approximately 1.5 times higher than plasma levels. When considering benefit and risk, the developmental and health benefits of breastfeeding should be considered along with the mother's clinical need for this drug, and potential adverse effects on the breastfed child from the drug or from the underlying maternal condition.

Data from 1 mother taking ivacaftor and lumacaftor while breastfeeding showed low levels of ivacaftor in milk. An international survey of cystic fibrosis centers found no adverse effects in breastfed infants of mothers taking these drugs. A task force of respiratory experts from Europe, Australia and New Zealand found that these drugs are probably safe during breastfeeding. Transient elevations in bilirubin and liver enzymes were found in 1 infant that could not definitively be attributed to the drugs in breastmilk. Until more data are available, monitoring of infant bilirubin and liver enzymes might be advisable during breastfeeding with maternal ivacaftor therapy. Examination of breastfed infants for cataracts has also been recommended.

Benefit should outweigh risk

Excreted into human milk: Unknown
Excreted into animal milk: Yes

Comments:
-If used during breastfeeding, consider monitoring infant liver enzymes and bilirubin, and examining infant for cataracts.
-Some authorities advise against breastfeeding until more data is available.

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