Benzathine Penicillin G and Breastfeeding

Summary of use during lactation

Limited information indicates benzathine penicillin G produces low levels in milk that are not expected to cause adverse effects in breastfed infants. Occasionally disruption of the infant's gastrointestinal flora, resulting in diarrhea or thrush have been reported with penicillins, but these effects have not been adequately evaluated. Benzathine penicillin G is acceptable in nursing mothers.

Drug levels in milk and infant serum

Maternal Levels. Two women received one dose of 2.4 million units of benzathine penicillin G intramuscularly 20 hours after delivery. Milk concentrations decreased from 30 units/L on the third day to 10 units/L on the fifth day. After the fifth day, milk levels were undetectable. The authors estimated that an exclusively breastfed infant would receive a maximum of 6 to 7 units daily.[1] Infant Levels. Relevant published information was not found as of the revision date.

Effects in breastfed infants

A breastfed 1-month-old infant with congenital syphilis developed a Herxheimer reaction 6 hours after its mother received 2.4 million units of benzathine penicillin G intramuscularly. However, the baby had also received 10 units of penicillin G at about the same time as the mother's injection. The reaction was possibly caused by penicillin in breastmilk.[2]

Effects on lactation and breastmilk

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

References

1. Borderon E, Soutoul J, Borderon J, et al. Excretion of antibiotics in human milk. Med Mal Infect 1975;5:373-6.
2. Rollier R, Rollier M, Bellouchi M. Herxheimer's reaction in maternal milk in early congenital syphilis. Bull Soc Fr Dermatol Syphiligr 1967;74:178-80.6070262 PubMed