Can a breastfeeding patient use Zosyn (piperacillin/tazobactam)?

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Last updated: December 29, 2025View editorial policy

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Zosyn Use During Breastfeeding

Zosyn (piperacillin/tazobactam) can be used during breastfeeding, as piperacillin is excreted in breast milk at low concentrations similar to other penicillins, which are classified as compatible with breastfeeding. 1

Safety Profile and Evidence

  • Piperacillin, the primary component of Zosyn, belongs to the penicillin class, which is consistently classified as "compatible" with breastfeeding across multiple international guidelines. 2

  • The FDA drug label confirms that piperacillin is excreted in human milk, though tazobactam concentrations in breast milk have not been specifically studied. 1

  • Penicillins and aminopenicillins are present in breast milk at low concentrations, making them among the safest antibiotic options for breastfeeding mothers. 2

Clinical Recommendations

  • The developmental and health benefits of breastfeeding should be considered along with the mother's clinical need for Zosyn, as stated in the FDA label. 1

  • Breastfeeding does not need to be interrupted when Zosyn is prescribed, following the same principles applied to other compatible penicillin antibiotics. 2

Infant Monitoring Considerations

  • Monitor the breastfed infant for gastrointestinal effects, including diarrhea or changes in stool pattern, due to potential alteration of intestinal flora. 2, 3

  • Watch for signs of candidiasis or other mild GI disturbances, though serious adverse events from penicillin exposure through breast milk are rare. 2

  • Be aware that antibiotics in breast milk could potentially cause falsely negative cultures if the breastfed infant develops fever requiring evaluation. 2, 3

Important Caveats

  • The safety profile assumes a full-term, healthy infant receiving standard recommended doses of Zosyn for appropriate duration. 2

  • If the infant is premature, jaundiced, or has other risk factors, closer monitoring is warranted, though this applies to all antibiotic use during breastfeeding rather than being specific to Zosyn. 4

  • The small amounts of antibiotic in breast milk should not be considered therapeutic for the infant—if the baby develops an infection, they require their own appropriate dosing. 2

References

Guideline

Safety of Antibiotics During Breastfeeding

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Guideline

Amoxicillin/Clavulanic Acid Safety During Breastfeeding

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Guideline

Treatment of Shingles in a Breastfeeding Mother

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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