Ceftazidime Dosing for UTI in CKD Stage 3a
For a patient with CKD stage 3a (eGFR 45-59 mL/min) and a urinary tract infection, ceftazidime should be dosed at 1-2 grams every 12 hours intravenously. 1
Dosing Algorithm Based on Renal Function
CKD stage 3a corresponds to a creatinine clearance of approximately 45-59 mL/min, which falls into the 30-50 mL/min dosing category for ceftazidime:
- CrCl >50 mL/min: Standard dosing of 1-2g every 8 hours 1
- CrCl 30-50 mL/min (includes CKD 3a): 1-2g every 12 hours 1
- CrCl 15-30 mL/min: 1-2g every 24 hours 1
- CrCl <15 mL/min: 1-2g every 36-48 hours 1
Pharmacokinetic Rationale
Ceftazidime elimination is entirely dependent on renal excretion through glomerular filtration, making dose adjustment essential in any degree of renal impairment. 2, 1 The drug is not metabolized and has minimal protein binding, with an elimination half-life that extends from 1.5-2 hours in normal renal function to approximately 10 hours in severe renal failure. 2
The clearance of ceftazidime directly correlates with creatinine clearance, ranging from 7.5 to 145.1 mL/min depending on renal function. 1
Critical Safety Considerations
Neurotoxicity Risk
Patients with any degree of renal impairment are at increased risk for ceftazidime encephalopathy, even with appropriate dose adjustments. 3 This complication can occur even when cerebrospinal fluid concentrations remain low, potentially mediated by accumulation of neurotoxic metabolites like quinolinic acid rather than ceftazidime itself. 3
Monitor closely for neurological symptoms including altered consciousness, confusion, or seizures, particularly if treatment extends beyond several days. 3
Dosing Pitfalls to Avoid
- Do not use standard 8-hourly dosing in CKD stage 3a - this will lead to drug accumulation and increased toxicity risk 1
- Avoid combining ceftazidime with other nephrotoxic agents when possible to prevent further deterioration of renal function 4
- Reassess renal function during treatment as acute changes may require further dose modification 1
Alternative Considerations for UTI in CKD
If the UTI is caused by carbapenem-resistant Enterobacterales (CRE), alternative agents with specific dosing recommendations include:
- Ceftazidime-avibactam: 2.5g IV every 8 hours for complicated UTI 5
- Aminoglycosides: Single-dose therapy may be appropriate for simple cystitis due to excellent urinary concentrations 5
However, for standard community-acquired UTI pathogens in CKD stage 3a, the adjusted ceftazidime dosing of 1-2g every 12 hours remains appropriate. 1