Can you take aztreonam 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.
Limited information indicates that aztreonam produces low levels in milk that are not expected to cause adverse effects in breastfed infants. Occasionally disruption of the infant's gastrointestinal flora, resulting in diarrhea or thrush, have been reported with beta-lactams, but these effects have not been adequately evaluated. A task force respiratory experts from Europe, Australia and New Zealand found that aztreonam is compatible with breastfeeding. Aztreonam is acceptable in nursing mothers.
Quoted from Aztreonam — Drugs and Lactation Database (LactMed®), National Institute of Child Health and Human Development, revised March 15, 2025.
How much aztreonam gets into breastmilk
Maternal Levels. After a single intramuscular dose of aztreonam 1 gram in 6 women, peak milk levels averaging 0.3 mg/L occurred 6 hours after the dose. In 6 other women given a single 1 gram dose of aztreonam intravenously, peak milk levels averaged 0.2 mg/L at 2.4 hours after the dose. Aztreonam was detectable (detection limit 0.09 mg/L) in milk between 2 and 8 hours after the intramuscular dose and 1.5 and 8 hours after the intravenous dose.
After a single intravenous dose of aztreonam 1 gram, milk levels ranging from 0.4 to 1 mg/L occurred 1 to 5 hours after the dose in 10 women with little variation in milk levels during this time in each woman. On average, levels were slightly higher 2 hours after the dose, but in individuals the peak level occurred at various times between 1 and 4 hours.
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 aztreonam while breastfeeding?
Limited information indicates that aztreonam produces low levels in milk that are not expected to cause adverse effects in breastfed infants. 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.
Does aztreonam pass into breastmilk?
LactMed's measured drug levels for aztreonam are quoted in full on this page, under "How much gets into breastmilk".
Do I need to pump and dump after taking aztreonam?
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 aztreonam
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.