Piperacillin
Piperacillin is a broad-spectrum penicillin antibiotic, often combined with tazobactam (a beta-lactamase inhibitor) to enhance its effectiveness against resistant bacteria. It is used to treat serious bacterial infections including pneumonia, skin infections, intra-abdominal infections, and septicemia. This medication is typically administered intravenously in hospital settings for moderate to severe infections.
Piperacillin is a broad-spectrum antibiotic used to treat various serious bacterial infections, often combined with tazobactam to overcome resistance.
This medication carries a boxed (black box) warning — the strongest type of FDA warning. Review the full prescribing information before use.
Key facts at a glance
- ATC
- J01CA12
- RxNorm
- 8339
- Generic
- Piperacillin
- Class
- atc-j01
- Brands
- Zosyn
- Availability
- rx
- Lactation
- unknown
- Routes
- —
- Forms
- solution, injection
- Regions
- US, EU, CN, JP
- Monitoring
- —
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Treats respiratory tract infections (including pneumonia), skin and soft tissue infections, intra-abdominal infections (such as appendicitis and peritonitis), urinary tract infections, and septicemia. Also used for febrile neutropenia and hospital-acquired infections.
Piperacillin works by inhibiting bacterial cell wall synthesis. It binds to penicillin-binding proteins (PBPs), preventing the cross-linking of peptidoglycan chains needed for bacterial cell wall strength and rigidity. Tazobactam inhibits beta-lactamase enzymes that would otherwise break down piperacillin, extending its spectrum of activity.
Requires prescription and is administered intravenously in healthcare settings. May cause allergic reactions (especially in penicillin-allergic patients), GI side effects, and rarely, serious adverse events like Clostridioides difficile infection. Dose adjustment may be needed in kidney impairment. May interact with certain medications including aminoglycosides and anticoagulants.
Official drug label
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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed July 26, 2026. · Read our editorial policy