Antipseudomonal penicillin + β-lactamase inhibitor Pregnancy: eMC §4.6: there are no or limited data in pregnant women. Animal studies have shown developmental toxicity but no evidence of teratogenicity at maternally toxic doses. Piperacillin and tazobactam cross the placenta. Use during pregnancy only if clearly indicated, i.e. only if the expected benefit outweighs the possible risks to the pregnant woman and foetus. Piperacillin is excreted in low concentrations in human milk (tazobactam concentrations in milk have not been studied); treat breast-feeding women only if the expected benefit outweighs the possible risks.

Piperacillin with tazobactam

Brand names: Tazocin

Used in: Sepsis Acute Appendicitis

An intravenous broad-spectrum antibacterial combining an extended-spectrum penicillin with a beta-lactamase inhibitor, used for serious infections including hospital-acquired pneumonia, intra-abdominal and complicated soft-tissue infections, and sepsis.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: 4 g piperacillin / 0.5 g tazobactam every 8 hours

Route: Intravenous infusion over 30 minutes

Frequency: Every 8 hours; every 6 hours for nosocomial (severe) pneumonia and for bacterial infections in neutropenic patients

eMC §4.2 (Piperacillin 2 g / Tazobactam 250 mg powder for solution for infusion). The dose and frequency depend on the severity and localisation of the infection and the expected pathogens. Adults and adolescents: the usual dose is 4 g piperacillin/0.5 g tazobactam every 8 hours. EVERY 6 HOURS is recommended for severe (nosocomial) pneumonia and for neutropenic adults with fever suspected to be due to bacterial infection; this regimen may also be applicable to other indicated infections when particularly severe. EVERY 8 HOURS applies to complicated urinary tract infections (including pyelonephritis), complicated intra-abdominal infections, and skin and soft tissue infections (including diabetic foot infections). TREATMENT DURATION: usually 5-14 days for most indications, guided by severity, pathogen(s) and clinical/bacteriological progress. HEPATIC IMPAIRMENT: no dose adjustment necessary. ELDERLY: no dose adjustment required with normal renal function or creatinine clearance above 40 mL/min. HAEMODIALYSIS: give one additional dose of 2 g/0.25 g after each dialysis period, because haemodialysis removes 30-50% of piperacillin in 4 hours. PAEDIATRIC: safety and efficacy in children aged 0-2 years has not been established and no data from controlled clinical studies are available.

Paediatric dose

Dose: 100 mg/kg

Route: Intravenous infusion over 30 minutes

Frequency: Every 8 hours

Max: Not to exceed 4 g piperacillin / 0.5 g tazobactam per dose over 30 minutes

eMC §4.2, paediatric population aged 2-12 years. dosePerKg refers to the PIPERACILLIN component only. Complicated intra-abdominal infections: 100 mg piperacillin / 12.5 mg tazobactam per kg body weight every 8 hours. Neutropenic children with fever suspected to be due to bacterial infection: 80 mg piperacillin / 10 mg tazobactam per kg body weight every 6 hours. RENAL IMPAIRMENT (children): creatinine clearance above 50 mL/min - no adjustment; creatinine clearance 50 mL/min or less - 70 mg piperacillin / 8.75 mg tazobactam per kg every 8 hours; on haemodialysis give one additional dose of 40 mg piperacillin / 5 mg tazobactam per kg after each dialysis period. Safety and efficacy in children aged 0-2 years has not been established. Verify against a children's formulary before prescribing.

Dose adjustments

Renal

eMC §4.2 (adults) - adjust the intravenous dose to the degree of actual renal impairment and monitor closely for signs of toxicity: creatinine clearance above 40 mL/min, no dose adjustment necessary; 20-40 mL/min, maximum suggested dose 4 g/0.5 g every 8 hours; below 20 mL/min, maximum suggested dose 4 g/0.5 g every 12 hours. For patients on haemodialysis, give one additional dose of 2 g/0.25 g after each dialysis period.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Paediatric weight-based calculator

Patient weight (kg)

Verify in a children's formulary

Contraindications

Hypersensitivity to the active substances or to any other penicillin-antibacterial agent (eMC §4.3)
History of acute severe allergic reaction to any other beta-lactam active substances, e.g. cephalosporin, monobactam or carbapenem (eMC §4.3)

Side effects

Diarrhoea - very common, occurring in about 1 patient in 10 (eMC §4.8)
Thrombocytopenia, anaemia, leukopenia; also nausea, vomiting, constipation, abdominal pain and dyspepsia (common)
Rash and pruritus; severe cutaneous adverse reactions including Stevens-Johnson syndrome, toxic epidermal necrolysis, DRESS and acute generalised exanthematous pustulosis (eMC §4.4 and §4.8)
Hypotension, phlebitis, thrombophlebitis and flushing; injection-site reaction, pyrexia and headache (common)
Pseudomembranous colitis; hypokalaemia; raised transaminases, alkaline phosphatase, bilirubin and creatinine; renal failure and tubulointerstitial nephritis
Serious/rare: anaphylactic and anaphylactoid shock, agranulocytosis, pancytopenia, seizures and encephalopathy (a beta-lactam class effect, especially with high doses in renal impairment), haemophagocytic lymphohistiocytosis (eMC §4.4)

Interactions

eMC §4.5 (interaction with other medicinal products) was not captured in this bundle - clinician to review it in the full SPC
Medicinal products that may lower potassium levels - eMC §4.4 notes hypokalaemia may occur in patients with low potassium reserves or receiving such concomitant products, and advises periodic electrolyte determinations

Clinical monograph

How it works

Piperacillin inhibits bacterial cell-wall synthesis by binding penicillin-binding proteins, while tazobactam irreversibly inhibits many bacterial beta-lactamases, restoring and extending activity against otherwise resistant Gram-negative and anaerobic organisms.

Prescribing in practice

It contains a penicillin and is contraindicated in patients with a history of severe hypersensitivity to penicillins or other beta-lactams — check allergy status before administration.
The dose must be reduced in renal impairment, and the significant sodium content should be considered in patients with cardiac failure or sodium restriction.
Reduced efficacy of combined hormonal contraception is a recognised antibiotic caution, and concurrent use with certain anticoagulants warrants closer monitoring.

Monitoring

Monitor renal function, electrolytes and full blood count during prolonged therapy, as neutropenia and electrolyte disturbance can occur.

Counselling the patient

This antibiotic is given by drip into a vein in hospital for serious infection.
Tell the team immediately about any allergy to penicillin or other antibiotics.
Report any rash, breathing difficulty, or severe or persistent diarrhoea during or after treatment.

Evidence & guidelines

Piperacillin with tazobactam is a widely used empirical agent in UK hospital sepsis and antimicrobial protocols for serious infection.

Reference: NICE NG139/NG143; UKHSA; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways