Is Procaine Penicillin G safe while breastfeeding?
Here is what NIH LactMed, the U.S. National Library of Medicine's authority on medicines and breastfeeding, reports about Procaine Penicillin G. This is a summary of that source — not our own verdict.
Effects on the breastfed infant
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.[ 3 ]
Effects on milk supply
Relevant published information was not found as of the revision date.
Levels in milk
Maternal Levels. No studies have reported milk penicillin G levels after administration of procaine penicillin G to the mother.[ 1 ] However, after 2 doses of 2 million units of aqueous penicillin G intramuscularly in 15 women, peak milk levels were 120 units/L and trough levels were 10 units/L. Two women received 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.[ 2 ] Milk levels after 2 to 2.4 million units of procaine penicillin G would be expected to be between those of similar doses of aqueous and benzathine penicillin G. Infant Levels. Relevant published information was not found as of the revision date.
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.