Guideline Summary: Use of Penicillins During Lactation

Safety Profile of β‑Lactam Antibiotics

β‑lactam antibiotics, including all penicillins, are routinely used and are considered completely safe for breastfeeding mothers, with no requirement to stop nursing. [@1]
Penicillins are classified as first‑line agents for lactating mothers and do not necessitate interruption of breast feeding. [@1]

Amoxicillin is rated “compatible” with lactation, representing the highest safety tier for antibiotics in this setting. [@3]
Amoxicillin/clavulanate (Augmentin) is explicitly recommended as a safe and effective option; it is FDA Category B and compatible with breastfeeding. [@4]

Penicillins and aminopenicillins are secreted into breast milk at low concentrations, resulting in minimal infant exposure. [@3]

First‑line therapy: Use amoxicillin or amoxicillin/clavulanate as the preferred agents for infections requiring antibiotics. [@4]
Penicillin allergy: Opt for cefalosporins (also safe in lactation) or macrolides such as azithromycin. [@3]
Breast‑feeding continuity: Do not discontinue breastfeeding while the mother is receiving penicillin therapy. [@3]

Infants of mothers on antibiotics should be observed for mild gastrointestinal effects (e.g., diarrhea, altered gut flora); serious adverse events are rare. [@3]
Antibiotic residues in breast milk may modestly disturb the infant’s intestinal microbiota, potentially causing mild diarrhea or gastroenteritis. [@3]
Presence of antibiotics in milk can lead to falsely negative cultures if the infant develops fever and requires evaluation. [@3]
The quantity of antibiotic transferred via milk is not therapeutic for the infant; any infant infection requires a separate, appropriate dosage. [@3]

The LactMed database of the National Institutes of Health provides peer‑reviewed, up‑to‑date information on medication safety during lactation. [@1]

Unnecessary cessation of breastfeeding when prescribing penicillins should be avoided; evidence consistently shows that the benefits of continued nursing outweigh the minimal risk of infant exposure to penicillins. [@3]