Although no information exists on the excretion of neomycin into milk, other aminoglycoside antibiotics are poorly excreted into breastmilk. Newborn infants apparently absorb small amounts of aminoglycosides, but serum levels are far below those attained when treating newborn infections and systemic effects of neomycin are unlikely. Older infants would be expected to absorb even less neomycin. Monitor the infant for possible effects on the gastrointestinal flora, such as diarrhea, candidiasis (e.g., thrush, diaper rash) or rarely, blood in the stool indicating possible antibiotic-associated colitis.
Oral, topical, ophthalmic or otic neomycin should result in very low levels in breastmilk and present negligible risk to the infant,[1][2] although topical application to the nipple may increase the risk of diarrhea in the infant. Only water-miscible cream or gel products should be applied to the breast because ointments may expose the infant to high levels of mineral paraffins via licking.[3]