Is Dicloxacillin safe while breastfeeding?
Here is what NIH LactMed, the U.S. National Library of Medicine's authority on medicines and breastfeeding, reports about Dicloxacillin. This is a summary of that source — not our own verdict.
Effects on the breastfed infant
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.
Levels in milk
Maternal Levels. After a single oral dose of 250 mg of dicloxacillin in 2 women, milk samples were assayed using a bioassay. Milk levels ranged from 200 to 300 mcg/L between 2 and 4 hours after the dose. The drug was undetectable (lower limit of assay not stated) in milk at 1 and 6 hours after the dose.[ 4 ] Three nursing mothers with mastitis were prescribed dicloxacillin 500 mg every 6 hours. They collected milk samples at 0, 1, 2, 3, 4, 5, and 6 hours after a dose on or after the fourth day of therapy by pumping both breasts and combining the resultant milk. Measurement with liquid chromatography mass spectrometry found that the average peak milk concentration was 67.6 mcg/L at 4 hours after the dose and the average concentration was 57.7 mcg/L. These values resulted in an average infant dosage of 8 mcg/kg daily, which is 0.03% of the maternal weight-adjusted dosage.[ 5 ] Infant Levels. Relevant published information was not found as of the revision date.
Alternatives LactMed lists
“No published information” means the studies do not exist yet — not that Dicloxacillin is known to be harmful, and not that it is known to be safe. Your prescriber or pharmacist can weigh your baby's age and whether a better-studied alternative would do the same job. Worth asking before stopping a medicine you need.
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.