Cefepime: Indications, Dosing, and Renal Adjustments
Cefepime is a fourth-generation cephalosporin indicated for pneumonia, febrile neutropenia, urinary tract infections, skin/soft tissue infections, and complicated intra-abdominal infections, with dosing that must be adjusted based on renal function to prevent neurotoxicity.
Approved Indications
Cefepime is FDA-approved for 1:
- Pneumonia (including hospital-acquired and ventilator-associated)
- Febrile neutropenia (empiric therapy)
- Urinary tract infections (uncomplicated and complicated, including pyelonephritis)
- Uncomplicated skin and skin structure infections
- Complicated intra-abdominal infections
Adult Dosing
Standard Dosing (Normal Renal Function)
For most serious infections, use 2 g IV every 8-12 hours 2. Specific recommendations:
- Hospital-acquired/ventilator-associated pneumonia: 2 g IV every 8 hours 3, 4
- Febrile neutropenia: 2 g IV every 8 hours 5
- Complicated intra-abdominal infections: 2 g IV every 8-12 hours 2
- Urinary tract infections: 2 g IV every 12 hours (can use every 8 hours for Pseudomonas) 6
Extended Infusions
For Pseudomonas aeruginosa infections, administer 2 g over 3 hours every 8 hours to optimize pharmacodynamic target attainment 7. This approach achieves free drug concentrations exceeding the MIC for ≥60% of the dosing interval, which is critical for time-dependent beta-lactam killing.
Renal Dose Adjustments (Critical)
Cefepime requires mandatory dose reduction in renal impairment to prevent neurotoxicity 8. The elimination half-life increases from 2.3 hours in normal renal function to 13.5 hours in severe renal impairment 8.
Recommended adjustments based on creatinine clearance (CrCl):
- CrCl >120 mL/min: 2 g every 6 hours (augmented renal clearance) 7
- CrCl 60-120 mL/min: 2 g every 8 hours (standard) 7
- CrCl 30-60 mL/min: 2 g every 12 hours 7
- CrCl 11-29 mL/min: 2 g every 24 hours 7
- CrCl <10 mL/min: 1 g every 24 hours 8
Hemodialysis Dosing
For intermittent hemodialysis: 1 g every 24 hours 6. Hemodialysis significantly removes cefepime, shortening the half-life from 13.5 hours to 2.3 hours during dialysis 8. For continuous renal replacement therapy (CRRT): 2 g every 12 hours 9.
Pediatric Dosing
Neonates and Infants
Age-based dosing is critical due to immature renal function:
- Neonates <14 days, gestational age <36 weeks: 30 mg/kg IV every 12 hours 6, 10
- Neonates <14 days, gestational age ≥36 weeks: 50 mg/kg IV every 12 hours 6, 10
- Neonates >14 days: 50 mg/kg IV every 12 hours 10
Children (2 months to 16 years)
Standard dose: 50 mg/kg IV every 8-12 hours, maximum 2 g per dose 11, 2. For serious Pseudomonas infections, use every 8 hours 6, 2.
Specific indications:
- Febrile neutropenia: 50 mg/kg every 8 hours 5
- Complicated intra-abdominal infections: 100 mg/kg/day divided every 12 hours 2
- Meningitis: Not recommended as first-line; use ceftazidime instead 11
Pediatric Renal Adjustments
For critically ill children with renal impairment: 100 mg/kg/day every 12 hours over 30 minutes, or as continuous infusion for augmented renal clearance 12. Therapeutic drug monitoring is mandatory given cefepime's narrow therapeutic window in children 12.
Critical Safety Considerations
Neurotoxicity Risk
Cefepime neurotoxicity occurs in up to 38.6% of patients with trough concentrations >15 mg/L 13. Risk factors include:
- Renal impairment without dose adjustment
- Elderly patients
- Pre-existing neurological conditions
Monitor for: confusion, encephalopathy, seizures, myoclonus. If neurotoxicity develops, discontinue immediately and consider hemodialysis for rapid drug removal 13.
Therapeutic Drug Monitoring
TDM is strongly recommended for non-critically ill patients to prevent overdosing 13. Target trough concentrations of 8-15 mg/L balance efficacy and toxicity risk. Model-based dosing software improves TDM accuracy compared to empiric adjustments 13.
Combination Therapy Considerations
When to Add Coverage
Add vancomycin or linezolid if:
- MRSA risk factors present (prior MRSA colonization, severe catheter-related infection) 3
- Gram-positive cocci on blood culture pending identification 14
Add aminoglycoside if:
Do NOT routinely combine with aminoglycosides for febrile neutropenia—meta-analyses show lower clinical response rates without mortality benefit 3.
Common Pitfalls
Failure to adjust for renal function: Most common cause of neurotoxicity. Always calculate CrCl before dosing 13, 8.
Underdosing in augmented renal clearance: Critically ill patients with CrCl >120 mL/min require increased frequency (every 6 hours) 7.
Using standard infusion times for Pseudomonas: Short 30-minute infusions may be inadequate; use 3-hour extended infusions 7.
Assuming all fourth-generation cephalosporins are equivalent: Cefepime has unique neurotoxicity profile requiring specific monitoring 13.
Prolonged empiric therapy without de-escalation: Median duration should be 7-8 days for most infections; longer courses increase MDRO risk 15.