Penicillins · Anti-infectives
Piperacillin-tazobactam
pip-tazo · Tazocin · Zosyn® · Tazocin®(brand names vary by market)
The broad empiric workhorse, and a stewardship problem waiting to be de-escalated.
Also: infusion
Mechanism
An extended-spectrum penicillin paired with a beta-lactamase inhibitor that protects it: Gram-positive, Gram-negative including Pseudomonas, and anaerobes in one agent.
Indications
- Hospital-acquired and ventilator-associated pneumonia
- Intra-abdominal infection
- Febrile neutropenia
- Complicated skin and soft tissue infection
- Sepsis of unknown source
Formulations
Dosing concepts
Extended infusion
Because killing is time-dependent, prolonging each infusion over several hours increases the time above MIC and improves outcomes in serious Gram-negative infection.
De-escalation
It is an empiric drug. Continuing it once cultures identify a narrower option is the commonest stewardship failure on any medical ward.
Concepts, not prescribing instructions. Practice numbers live in current references and local protocols.
Pharmacokinetics
- Bioavailability
- Parenteral only
- Half-life
- ~1 h
- Elimination
- renal: Dose and interval adjusted by creatinine clearance and by renal replacement therapy
- Protein binding
- ~30%
Adverse effects
- Diarrhoea and C. difficilecommon & serious
- Acute kidney injuryseriousNotably higher when combined with vancomycin, a combination used constantly in empiric sepsis therapy.
- Hypokalemiacommon
- Rashcommon
- Neutropenia with prolonged coursesserious
Contraindications & precautions
Contraindications
- Severe penicillin hypersensitivity
Precautions
- Concurrent vancomycin
- Renal impairment
- Prolonged courses
Interactions
Monitoring
Renal function daily on combination therapy
The vancomycin pairing raises AKI risk substantially
Potassium
It causes renal potassium wasting
Cultures and the de-escalation decision
The most valuable thing anyone does with this drug is stop it
Counselling points
- Given as an infusion, sometimes over several hours, which is deliberate.
- Report diarrhoea or a rash.
- Blood tests will be checked regularly while you are on it.
Clinical pearls
- The piperacillin-tazobactam plus vancomycin combination is one of the best-documented nephrotoxic pairings in hospital medicine, and it is prescribed together every day. Knowing that changes how closely the creatinine is watched.
- Its anaerobic coverage means adding metronidazole is usually redundant, a very common duplication.
References & review
- Piperacillin-tazobactam product monograph (consult the current version for your market) (monograph)
- Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed. (reference-work)
Last reviewed 2026-08-16 · jurisdiction: global · drug information changes; verify against current references before practice use.