LACTOLOGY FOUNDATION

Streptomycin combinations (ATC A07AA54) are oral intestinal antibiotic preparations in which streptomycin is the main active component, combined with other antimicrobials for the treatment of gastrointestinal infections. Because orally administered streptomycin is poorly absorbed from the gastrointestinal tract, systemic exposure is low and the expected transfer into breast milk from these intestinal combinations is minimal, although specific lactation data for individual products are sparse.atcddd.fhi+3

Pharmacological class and composition

A07AA54 includes fixed‑dose combinations where streptomycin has ATC classification priority and is formulated with other intestinal antiinfectives for local action in the gut. These products are used primarily for intestinal infections, decontamination, or related gastrointestinal indications, with streptomycin providing aminoglycoside activity against susceptible aerobic gram‑negative and some gram‑positive bacteria.atcddd.fhi+2

Mechanism of action

Streptomycin is an aminoglycoside that binds to the 30S ribosomal subunit, causing misreading of mRNA, inhibition of protein synthesis, and ultimately bactericidal activity. In combination products, streptomycin’s action may be complemented by agents such as penicillins or other antibiotics acting on different bacterial targets, yielding additive or synergistic suppression of pathogenic intestinal flora.drugbank+2

Pharmacokinetics relevant to lactation

Streptomycin and dihydrostreptomycin are poorly absorbed from the gastrointestinal tract in both humans and animals, and most of an oral dose is recovered in the feces. This limited oral bioavailability means maternal plasma levels after intestinal administration are very low, which in turn implies that only small amounts, if any, would be available for transfer into breast milk.ema.europa+2

Maternal toxicity and adverse effects

Systemically, streptomycin can cause ototoxicity, nephrotoxicity, and neuromuscular blockade, especially with high cumulative doses or in patients with renal impairment. However, such toxicities are mainly associated with parenteral use; with oral intestinal combinations, adverse effects are more likely to involve gastrointestinal symptoms (nausea, vomiting, diarrhea) and alterations in gut microbiota rather than significant systemic toxicity.pmc.ncbi.nlm.nih+3

Excretion into breast milk

Small amounts of streptomycin are excreted into human milk after systemic administration. Aminoglycosides as a class are known to enter breast milk in low concentrations but are poorly absorbed from the infant gut, and are therefore considered generally compatible with breastfeeding by several expert bodies. For oral intestinal streptomycin combinations, the combination of low maternal plasma levels and poor infant oral absorption suggests that clinically relevant infant exposure via milk is unlikely.ema.europa+4

Reported effects in breastfed infants

There are no specific reports of adverse outcomes in infants breastfed by mothers receiving intestinal A07AA54 streptomycin combinations. More broadly, guidance on streptomycin and aminoglycosides in breastfeeding notes that breastfed infants should be monitored for diarrhea and oral thrush, but serious systemic toxicity has not been documented at the low levels expected from maternal therapeutic use.msdmanuals+2

Impact on lactation and breast milk

No data indicate that streptomycin or its intestinal combinations impair milk production or alter the hormonal regulation of lactation. General reviews on medication use during breastfeeding conclude that many antibiotics, including aminoglycosides, can be used when necessary, with attention to dose and duration, without significant impact on breastfeeding itself.sps+3

Clinical use in breastfeeding

For breastfeeding women who require oral streptomycin combinations for documented intestinal infections or decontamination, the low systemic absorption and expected minimal milk transfer support continued breastfeeding in many cases after individualized assessment. Some guidelines recommend cautious use—especially in neonates or medically fragile infants—with consideration of alternative agents if equally effective options with more robust lactation data exist.atcddd.fhi+4

Infant monitoring recommendations

When a lactating mother is treated with an A07AA54 streptomycin combination, routine infant monitoring focuses on clinical signs rather than drug level measurements. Caregivers should observe the infant for gastrointestinal disturbances (diarrhea, constipation, blood in stool), oral or diaper candidiasis, or unusual irritability, and seek medical review if such symptoms develop.sps+3

Risk–benefit assessment

In situations where streptomycin combinations are clearly indicated and contribute significantly to controlling intestinal infection or preventing serious complications, maternal benefit and the importance of maintaining breastfeeding usually outweigh the small, theoretical risks to the infant. For less critical indications or when suitable alternatives with extensive breastfeeding experience are available, preferential use of those alternatives may be reasonable, particularly in premature or high‑risk infants, while still valuing the benefits of continued breastfeeding.atcddd.fhi+5

Key counselling points

Healthcare professionals should explain that streptomycin in A07AA54 combinations belongs to the aminoglycoside class, is poorly absorbed orally, and is expected to appear in breast milk only in small amounts that are unlikely to harm the infant, though monitoring is advised. Shared decision‑making should address the indication, dose and duration of therapy, the infant’s age and health, and the strong benefits of ongoing breastfeeding, with advice to watch for gastrointestinal or candidal symptoms in the infant during treatment.ema.europa+5