Drug Levels and Effects:

Summary of Use during Lactation:

Similar to other aminoglycoside antibiotics, streptomycin is 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 streptomycin are unlikely. Older infants would be expected to absorb even less streptomycin 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.

Drug Levels:

Maternal Levels.

Forty-six mothers receiving intramuscular streptomycin 250,000 MU had milk streptomycin levels measured hourly after a dose. The peak concentration in milk averaged 0.64 MU and occurred 9 hours after the dose. Mothers with unilateral mastitis had higher levels in the breast with mastitis than in the unaffected breast.[1] Although it is not clear what the above dose was in milligrams in this older Russian paper, if the same proportion is used, a 1 g intramuscular dose would result in a peak streptomycin milk level of 2.6 mg/L.

Infant Levels.

Relevant published information was not found as of the revision date.

Effects in Breastfed Infants:

Relevant published information was not found as of the revision date.

Possible Effects on Lactation:

One observational study found no inhibition of lactation by streptomycin.[1]


1. Rudneva NN. [Effect of penicillin and streptomycin on lactation in parturients]. Akush Ginekol (Mosk). 1967;43:48-52. PMID:5629407

Substance Identification:

Substance Name:


CAS Registry Number:


Drug Class:

  • Antiinfective Agents

  • Antibacterial Agents

  • Aminoglycosides

  • Antitubercular Agents

  • Administrative Information:

    LactMed Record Number:


    Last Revision Date:

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