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Penicillin g benzathine Pregnancy and Breastfeeding Warnings

Penicillin g benzathine is also known as: Bicillin L-A, Isoject Permapen

Medically reviewed by Last updated on Jul 2, 2019.

Penicillin g benzathine Pregnancy Warnings

This drug should be used during pregnancy only if clearly needed.

AU TGA pregnancy category: A
US FDA pregnancy category: B

Animal studies have failed to reveal evidence of fetal harm. No positive evidence of adverse effects on the fetus observed during human use of penicillins; however, there are no controlled data in human pregnancy.

AU TGA pregnancy category A: Drugs which have been taken by a large number of pregnant women and women of childbearing age without any proven increase in the frequency of malformations or other direct or indirect harmful effects on the fetus having been observed.

US FDA pregnancy category B: Animal reproduction studies have failed to demonstrate a risk to the fetus and there are no adequate and well-controlled studies in pregnant women.

See references

Penicillin g benzathine Breastfeeding Warnings

Soluble penicillin is excreted in breast milk.

A 2.4 million unit IM dose was administered to 2 women 20 hours after delivery. Milk levels were 30 units/L on the 3rd day, 10 units/L on the 5th day, and undetectable thereafter. According to authors, a maximum of 6 to 7 units estimated to be ingested per day by an exclusively breastfed infant.

A Herxheimer's reaction occurred in a 1-month-old breastfed infant with congenital syphilis 6 hours after a 2.4 million unit IM dose was administered to the mother; the infant had also received 10 units of penicillin G at about the time of the maternal dose. The reaction was possibly due to penicillin in breast milk.

Disruption of infant's gastrointestinal flora (resulting in diarrhea or thrush) reported occasionally with penicillins; such effects have not been adequately evaluated.

Use is considered acceptable; caution is recommended.

Excreted into human milk: Yes

-The effects in the nursing infant are unknown.
-Limited data indicate that low levels in milk from single maternal doses are not expected to cause harmful effects in nursing infants.

See references

References for pregnancy information

  1. "Product Information. Bicillin L-A (penicillin)." Monarch Pharmaceuticals Inc, Bristol, TN.
  2. Cerner Multum, Inc. "Australian Product Information." O 0

References for breastfeeding information

  1. United States National Library of Medicine "Toxnet. Toxicology Data Network. Available from: URL:" ([cited 2013 -]):
  2. Cerner Multum, Inc. "Australian Product Information." O 0
  3. "Product Information. Bicillin L-A (penicillin)." Monarch Pharmaceuticals Inc, Bristol, TN.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.