Is Gentamicin safe while breastfeeding?
Here is what NIH LactMed, the U.S. National Library of Medicine's authority on medicines and breastfeeding, reports about Gentamicin. This is a summary of that source — not our own verdict.
Effects on the breastfed infant
Bloody stools in one 5-day-old infant were possibly caused by concurrent maternal administration of clindamycin and gentamicin.[ 5 ] A 2-month-old infant breastfed since birth. His mother had taken many medications during pregnancy, but she did not recall their identity. She developed mastitis and was treated with amoxicillin-clavulanic acid 1 gram orally every 12 hours and gentamicin 160 mg intramuscularly once daily. The infant was breastfed for 10 minutes starting 15 minutes after the first dose of both drugs. About 20 minutes later, the infant developed a generalized urticaria which disappeared after 30 minutes. A few hours later, the infant breastfed again and the urticaria reappeared after 15 minutes and disappeared after an hour. After switching to formula feeding and no further infant exposure to penicillins, the reaction did not reappear with follow-up to 16 months of age. The adverse reaction was probably caused by the antibiotics in breastmilk. The drug that caused the reaction cannot be determined, but it was most likely the amoxicillin-clavulanic acid.[ 6 ]
Effects on milk supply
Relevant published information was not found as of the revision date.
Levels in milk
Maternal Levels. In 5 or 10 women (article unclear) given a single dose of gentamicin 80 mg intramuscularly in the early postpartum period, average milk levels were 157 mcg/L 1 hour after the dose, 156 mcg/L at 3 hours after the dose, 137 mcg/L at 6 hours after the dose and 3 mcg/L at 12 hours after the dose.[ 2 ] After implantation of 90 gentamicin-impregnated beads into the femur of one mother with osteomyelitis, milk levels ranged from 70 to 190 mcg/L at various times over the following 23-day period.[ 3 ] Ten mothers nursing newborn infants were given prophylactic gentamicin 80 mg intramuscularly 3 times a day. On day 4, milk gentamicin levels were as follows: 420 mcg/L 1 hour after the dose; 480 mcg/L 3 hours after the dose; 490 mcg/L at 5 hours after the dose; and, 410 mcg/L 7 hours after the dose.[ 4 ] Infant Levels. In the infants of 5 or 10 women (article unclear) given a single dose of gentamicin 80 mg intramuscularly, none of the breastfed neonates had detectable gentamicin serum levels.[ 2 ] Ten mothers nursing newborn infants were given prophylactic gentamicin 80 mg intramuscularly 3 times a day. One hour after nursing on day 4, gentamicin was undetectable ( 270 mcg/L) in the serum of 5 of the infants and averaged 410 mcg/L (range 340 to 490 mcg/L) in the other five infants who nursed one hour after a maternal dose.[ 4 ]
Source: NIH LactMed (National Library of Medicine).
Educational summary of an authoritative source — not medical advice. Never start, stop, or change a medicine while breastfeeding without confirming with your doctor.