Is Procaine Penicillin G safe while breastfeeding?
Here is what LactMed, the Drugs and Lactation Database published by the U.S. National Institute of Child Health and Human Development (NICHD), reports about Procaine Penicillin G. The text below is quoted from that source — it is not our own verdict.
Summary of use during breastfeeding
Limited information indicates 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. Procaine penicillin G is acceptable in nursing mothers.
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: Drugs and Lactation Database (LactMed), National Institute of Child Health and Human Development (NICHD), via NCBI Bookshelf, record “Procaine Penicillin G” (LM226). LactMed on NCBI Bookshelf. LactMed is a registered trademark of the U.S. Department of Health and Human Services.
Educational summary of an authoritative source — not medical advice. Never start, stop, or change a medicine while breastfeeding without confirming with your doctor.