Is Tobramycin safe while breastfeeding?

Summary of use during breastfeeding

Tobramycin is poorly excreted into breastmilk. Newborn infants apparently absorb small amounts of other aminoglycosides, but serum levels with three times daily dosages are far below those attained when treating newborn infections and systemic effects of tobramycin are unlikely. Older infants would be expected to absorb even less tobramycin. Because there is little variability in the milk tobramycin levels during multiple daily dose regimens, timing breastfeeding with respect to the dose is of little or no benefit in reducing infant exposure. Data are not available with single daily dose regimens. 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.

Maternal use of an ear drop or eye drop that contains tobramycin presents little or no risk for the nursing infant.[1] A task force respiratory experts from Europe, Australia and New Zealand found that inhaled tobramycin is compatible with breastfeeding.[2]

Effects on the breastfed infant

An infant was breastfed (extent not stated) until the 4th month postpartum. At 2 months of age, his mother was given a 2-week course of tobramycin 150 mg three times daily plus meropenem for a cystic fibrosis exacerbation. infant displayed no change in stool pattern during the maternal treatment and had normal renal function at 6 months of age.[5,6]

Effects on milk supply

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

Levels in milk

Maternal Levels. After a single 80 mg intramuscular dose of tobramycin in 5 women, milk levels were measured every hour for 6 hours. Only trace levels were detected in 4 of the samples from 1 to 8 hours after the dose. In the fifth woman, milk levels ranged from 0.4 to 0.52 mg/L over 8 hours, with the highest level found at 4 hours after the dose.[3]

In one patient who received 80 mg of tobramycin every 8 hours by intramuscular injection, milk levels were 0.6 mg/L 1 hour after the dose and 0.58 mg/L 8 hours after the dose.[4]

At 2 months postpartum, a woman was receiving intravenous tobramycin 150 mg 3 times daily plus meropenem for cystic fibrosis. Four days after beginning, milk tobramycin levels were undetectable (<0.18 mg/L) before the infusion and in 6 milk samples taken from 1 to 5 hours after the infusion.[5]

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