Is Floxacillin safe while breastfeeding?
Here is what LactMed, the Drugs and Lactation Database published by the U.S. National Institute of Child Health and Human Development (NICHD), reports about Floxacillin. The text below is quoted from that source — it is not our own verdict.
Summary of use during breastfeeding
Floxacillin (flucloxacillin) is not approved for marketing in the United States by the U.S. Food and Drug Administration. It is acceptable to use during breastfeeding and is frequently used abroad to treat mastitis in nursing mothers.[1-3] Limited information indicates that floxacillin levels in milk are low and 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 penicillins, but these effects have not been adequately evaluated. Floxacillin is acceptable in nursing mothers.
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. One report states that the manufacturer supplied information on floxacillin excretion into breastmilk. After a 250 mg oral dose, a milk level of 0.1 mg/L was measured. Further details are lacking.[4] This value is consistent with that of other penicillins.
Infant Levels. Relevant published information was not found as of the revision date.
Alternatives LactMed lists
Floxacillin in pregnancy
LactMed covers breastfeeding only. For what the NHS and the US prescribing label say about pregnancy, see:
“No published information” means the studies do not exist yet — not that Floxacillin 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: Drugs and Lactation Database (LactMed), National Institute of Child Health and Human Development (NICHD), via NCBI Bookshelf, record “Floxacillin” (LM1083). LactMed on NCBI Bookshelf. LactMed is a registered trademark of the U.S. Department of Health and Human Services.
Educational summary of an authoritative source — not medical advice. Never start, stop, or change a medicine while breastfeeding without confirming with your doctor.