Can you take zafirlukast while breastfeeding?
What LactMed says
The National Library of Medicine’s own summary, quoted in full. We do not write a verdict of our own on this question, and we do not compress theirs into a label.
No published information is available on the use of zafirlukast during breastfeeding; however, manufacturer's data indicate that the dose in milk is low. Zafirlukast has been used in children as young as 12 months of age. International guidelines consider that leukotriene receptor antagonists can be used during breastfeeding.
Quoted from Zafirlukast — Drugs and Lactation Database (LactMed®), National Institute of Child Health and Human Development, revised July 15, 2024.
What LactMed would consider instead
LactMed ends this record by naming the drugs it would consider in place of zafirlukast. Whether any of them fits depends on what you are treating — this is the database’s list, not a recommendation from us.
How much zafirlukast gets into breastmilk
Maternal Levels. Relevant published information was not found as of the revision date.
The manufacturer reports that after administration of zafirlukast 40 mg twice daily to lactating women (number not reported), average steady-state milk concentrations were 50 mcg/L. Using these data, a fully breastfed infant would be expected to receive about 0.6% of the maternal weight-adjusted dosage.
Infant Levels. Relevant published information was not found as of the revision date.
What has been seen in breastfed infants
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.
Frequently asked questions
Can you take zafirlukast while breastfeeding?
No published information is available on the use of zafirlukast during breastfeeding; however, manufacturer's data indicate that the dose in milk is low. The full record is quoted on this page, and the decision is one to make with the person who prescribed it — LactMed itself states it is not a substitute for professional judgement.
What can I take instead of zafirlukast while breastfeeding?
LactMed lists Beclomethasone, Cromolyn, Montelukast, Terbutaline, Theophylline as alternate drugs to consider. That is the database's own list for this drug — whether any of them suits you depends on what you are treating.
Does zafirlukast pass into breastmilk?
LactMed's measured drug levels for zafirlukast are quoted in full on this page, under "How much gets into breastmilk".
Do I need to pump and dump after taking zafirlukast?
LactMed does not frame its records that way — it reports measured drug levels in milk and what has been observed in breastfed infants, which is what this page quotes. "Pump and dump" advice for a specific drug and dose should come from your clinician or a pharmacist, not from a general rule.
More on zafirlukast
LactMed states that the information it presents is not a substitute for professional judgement, and that you should consult your healthcare provider for breastfeeding advice related to your particular situation. Nothing on this page is medical advice.