Skip to Content
Here’s what to ask a doctor about hereditary angioedema

Piperacillin / tazobactam Pregnancy and Breastfeeding Warnings

Piperacillin / tazobactam is also known as: Zosyn

Piperacillin / tazobactam Pregnancy Warnings

Animal studies have failed to reveal evidence of fetotoxicity or teratogenicity. Both components cross the placenta in humans. There are no controlled data in human pregnancy. AU TGA pregnancy category B1: Drugs which have been taken by only a limited number of pregnant women and women of childbearing age, without an increase in the frequency of malformation or other direct or indirect harmful effects on the human fetus having been observed. Studies in animals have not shown evidence of an increased occurrence of fetal damage. 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.

This drug should be used during pregnancy only if clearly needed and the benefit outweighs the risk to the fetus. AU TGA pregnancy category: B1 US FDA pregnancy category: B

See references

Piperacillin / tazobactam Breastfeeding Warnings

Use is considered acceptable; the benefit should outweigh the risk to the mother and infant. Caution is recommended. Excreted into human milk: Yes (piperacillin [in small amounts]); Unknown (tazobactam) Excreted into animal milk: Yes (tazobactam) Comments: -Low levels of piperacillin in milk are not expected to cause harmful effects in the nursing infant. -Disruption of infant's gastrointestinal flora (resulting in diarrhea or thrush) reported occasionally with penicillins, but such effects have not been adequately evaluated.

According to limited data, maternal doses of piperacillin up to 12 g produce low levels in breast milk. Piperacillin (4 g IV every 8 hours) was administered to 8 women for at least 3 days; milk levels were measured after 2 subsequent doses. In the 3 hours after each dose, milk levels ranged from 0.49 to 1.5 mg/L and 1.1 to 1.9 mg/L after the first and second dose, respectively; peak milk levels were reached 2 to 3 hours after dosing.

See references

References for pregnancy information

  1. Bourget P, Sertin A, LesneHulin A, Fernandez H, Ville Y, VanPeborgh P "Influence of pregnancy on the pharmacokinetic behaviour and the trans-placental transfer of the piperacillin-tazobactam combination." Eur J Obstet Gynecol Reprod Biol 76 (1998): 21-7
  2. Cerner Multum, Inc. "Australian Product Information." O 0
  3. "Product Information. Zosyn (piperacillin-tazobactam)." Lederle Laboratories, Wayne, NJ.
  4. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
  5. Melbourne: Therapeutic Guidelines Limited "eTG complete [Online] Available from: URL:" ([2014, Nov -]):

References for breastfeeding information

  1. Cerner Multum, Inc. "Australian Product Information." O 0
  2. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
  3. United States National Library of Medicine "Toxnet. Toxicology Data Network. Available from: URL:" ([cited 2013 -]):
  4. "Product Information. Zosyn (piperacillin-tazobactam)." Lederle Laboratories, Wayne, NJ.
  5. Melbourne: Therapeutic Guidelines Limited "eTG complete [Online] Available from: URL:" ([2014, Nov -]):

Disclaimer: Every effort has been made to ensure that the information provided by Cerner Multum, Wolters Kluwer Health and is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This drug information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate that the drug or combination is safe, effective, or appropriate for any given patient. Multum Information Services, Inc. does not assume any responsibility for any aspect of healthcare administered with the aid of information Multum provides. Copyright 2000-2008 Multum Information Services, Inc. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse, or pharmacist.