Antipseudomonal penicillin + β-lactamase inhibitor

Piperacillin with tazobactam

Brand names: Tazocin

Adult dose

Dose: 4.5g IV every 8h (or every 6h in severe sepsis); extended infusion 4h often used

Route: IV

Frequency: q6-8h

Paediatric dose

Dose: 90 mg/kg

Route: IV

Frequency: q8h

Age bands

0–1m: 90 mg/kg IV q8h
1–216m: 90 mg/kg (max 4.5g) IV q6-8h

Dose adjustments

Renal

Reduce if CrCl <40 mL/min

Paediatric weight-based calculator

Patient weight (kg)

Clinical pearls

Hospital-acquired pneumonia, intra-abdominal sepsis, neutropenic sepsis, complicated UTI
Cover for Pseudomonas; reduce frequency for renal function

Contraindications

Penicillin allergy
Severe β-lactam hypersensitivity

Side effects

Diarrhoea
C. difficile infection
Rash
Hepatotoxicity
Cytopenias
Hypokalaemia
Acute kidney injury (with vancomycin)
Seizures (high dose / renal impairment)

Interactions

Methotrexate
Warfarin
Aminoglycosides (compatibility)
Vancomycin (AKI risk)

Monitoring

FBC
U&E
LFTs
CRP

Reference: BNFc; BNF; NICE NG139/NG143; UKHSA; https://bnf.nice.org.uk/drugs/piperacillin-with-tazobactam/. Verify against your local formulary and the latest BNF before prescribing.

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways