Ceftolozane/Tazobactam Dosing
Standard Dosing for Normal Renal Function
For adults with normal renal function (CrCl >50 mL/min), administer ceftolozane/tazobactam 1.5 g (1 g/0.5 g) intravenously every 8 hours as a 1-hour infusion 1. This dosing achieves bactericidal activity with >90% probability of target attainment against susceptible pathogens including multidrug-resistant Pseudomonas aeruginosa and ESBL-producing Enterobacteriaceae 2.
The pharmacodynamic target for ceftolozane is maintaining free drug concentrations above the MIC for approximately 30-40% of the dosing interval, which is substantially lower than other cephalosporins 1. For tazobactam, the target is 20% of time above the minimum effective concentration of 1 mg/L 2.
Renal Impairment Dosing
Mild Renal Impairment (CrCl 30-50 mL/min)
- No dose adjustment required - exposures increase only 1.2-1.4 fold, which remains within safety margins 3
Moderate Renal Impairment (CrCl 15-29 mL/min)
- Loading dose: 750 mg (500 mg/250 mg)
- Maintenance: 375 mg (250 mg/125 mg) every 8 hours 3
- Exposures increase 2.2-2.5 fold without adjustment, necessitating dose reduction
Severe Renal Impairment (CrCl <15 mL/min, not on dialysis)
- Loading dose: 750 mg (500 mg/250 mg)
- Maintenance: 150 mg (100 mg/50 mg) every 8 hours 3
- Dose-normalized exposures increase 3.8-4.4 fold without adjustment
End-Stage Renal Disease on Hemodialysis
For patients on intermittent hemodialysis, use a loading dose of 750 mg (500 mg/250 mg), followed by maintenance doses of 150 mg (100 mg/50 mg) every 8 hours 3. Administer doses after hemodialysis on dialysis days, as approximately 66% of ceftolozane and 56% of tazobactam are removed during a dialysis session 3.
An alternative strategy supported by case report data involves standard dosing of 150 mg (100 mg/50 mg) every 8 hours plus supplemental doses of 1.5 g (1 g/0.5 g) three times weekly immediately following hemodialysis 4. This approach achieved >90% time above MIC with calculated clearances matching non-dialysis dosing.
For hospital-acquired/ventilator-associated pneumonia specifically in ESRD patients, Monte Carlo simulations support a middle-dose regimen of 2.25 g (1.5 g/0.75 g) loading dose followed by 450 mg (300 mg/150 mg) every 8 hours to achieve >90% probability of target attainment in epithelial lining fluid 5. The higher dose compensates for reduced lung penetration while avoiding excessive plasma exposures.
Augmented Renal Clearance (CrCl >120 mL/min)
In critically ill patients with augmented renal clearance (CrCl 120-200 mL/min), extend the infusion time to 4 hours while maintaining the standard 1.5 g dose every 8 hours 6. This prolonged infusion strategy increases the percentage of time above MIC without requiring dose escalation, which is consistent with β-lactam pharmacodynamic principles 7.
Standard dosing achieves >91% bactericidal target attainment up to MIC of 4 mg/L even with augmented clearance 2, but prolonged infusion provides additional margin for pathogens at the upper end of susceptibility.
Critical Considerations
β-Lactam Pharmacodynamics in Sepsis
As a β-lactam antibiotic, ceftolozane requires optimization of time above MIC rather than peak concentrations 7. Always initiate with a full loading dose regardless of renal function, as loading doses are unaffected by renal impairment but subsequent maintenance dosing requires adjustment 7. In septic patients, expanded extracellular volume from fluid resuscitation increases the volume of distribution, potentially reducing initial drug levels 7.
Hepatic Impairment
No dose adjustment is required for hepatic dysfunction 1. Ceftolozane is predominantly excreted unchanged in urine (≥92%) with minimal hepatic metabolism.
Common Pitfalls
- Avoid underdosing in augmented renal clearance: Standard doses may be subtherapeutic; use prolonged infusions
- Do not give dialysis doses pre-dialysis: Substantial drug removal occurs during hemodialysis; always dose post-dialysis 3
- Monitor for neurotoxicity in renal impairment: While less neurotoxic than some β-lactams, accumulation can occur with inadequate dose adjustment 8
- Calculate creatinine clearance accurately: Use Cockcroft-Gault equation adjusting for actual body weight; in obesity, consider adjusted body weight calculations