What is the recommended dosage of Cefepime (Cefepime) for a patient undergoing peritoneal dialysis with impaired renal function?

Cefepime Dosing in Peritoneal Dialysis Patients

For patients on peritoneal dialysis requiring a 6-week course of cefepime, the recommended dosage is 2 g every 48 hours. 1

Dosing Considerations in Peritoneal Dialysis

Cefepime is primarily eliminated by the kidneys, requiring dosage adjustment in patients with impaired renal function, including those on peritoneal dialysis. The FDA-approved drug label provides specific guidance for dosing in patients on continuous ambulatory peritoneal dialysis (CAPD):

• For standard infections: 2 g every 48 hours 1
• This dosing interval applies regardless of the initial dose (500 mg, 1 g, or 2 g)

Pharmacokinetic Rationale

Pharmacokinetic studies support this dosing recommendation:

• Cefepime has an elimination half-life of approximately 18 hours in peritoneal dialysis patients 2
• About 26% of the dose is excreted into peritoneal dialysis fluid over a 72-hour period 2
• A dose of 1-2 g every 48 hours maintains antibiotic levels above the MIC90 for most susceptible bacteria in both plasma and peritoneal fluid 2

Important Monitoring Considerations

When administering cefepime to peritoneal dialysis patients, several monitoring parameters are essential:

• Serum drug concentrations: Consider monitoring to ensure adequate drug levels without excessive accumulation 3
• Neurological status: Watch for signs of cefepime-induced encephalopathy (confusion, disorientation, myoclonus, seizures), which occurs at a higher rate (7.5%) in end-stage renal disease patients 4
• Pre-existing CNS conditions: Patients with pre-existing central nervous system morbidity are at significantly higher risk for cefepime-induced encephalopathy 4

Pitfalls and Caveats

1. Lack of specific peritoneal dialysis data in guidelines: Most renal dosing guidelines focus on hemodialysis rather than peritoneal dialysis. The American Thoracic Society/CDC/IDSA guidelines specifically note: "Data currently are not available for patients receiving peritoneal dialysis. Until data become available, begin with doses recommended for patients receiving hemodialysis and verify adequacy of dosing using serum concentration monitoring." 3

2. Risk of neurotoxicity: Even with appropriate dose adjustment, ESRD patients remain at risk for cefepime-induced encephalopathy. This can occur regardless of daily dose, even with doses as low as 0.5 g/day 4

3. Consideration of infection site: For severe or deep-seated infections, therapeutic drug monitoring may be particularly valuable to ensure adequate drug concentrations at the infection site

4. Duration of therapy: For the 6-week course specified in the question, careful monitoring for cumulative toxicity is essential, particularly neurological effects

Practical Application

For a patient on peritoneal dialysis requiring 6 weeks of cefepime therapy:

1. Start with 2 g IV every 48 hours
2. Monitor for clinical response and signs of toxicity
3. Consider therapeutic drug monitoring, especially if:
   • Patient has pre-existing CNS disease
   • Clinical response is inadequate
   • Signs of toxicity develop

By following these recommendations and monitoring parameters, cefepime can be administered safely and effectively to peritoneal dialysis patients requiring extended antimicrobial therapy.