What is the appropriate dose of cefepime (Cefepime) for a 71-year-old male with a urinary tract infection (UTI) and impaired renal function, with a creatinine level of 0.7 and a creatinine ratio of 40?

Cefepime Dosing for UTI in 71-Year-Old Male with Renal Impairment

For this 71-year-old male with UTI and a creatinine clearance of approximately 40 mL/min, cefepime should be dosed at 1 gram every 24 hours (once daily).

Renal Function Assessment

The patient's renal function parameters indicate moderate renal impairment:

• Serum creatinine: 0.7 mg/dL
• BUN: 27 mg/dL
• BUN/Creatinine ratio: 40
• Estimated creatinine clearance: ~40 mL/min (based on the provided ratio)

This creatinine clearance of 40 mL/min places the patient in the moderate renal impairment category requiring dose adjustment 1.

Recommended Dosing Regimen

For UTI with creatinine clearance of 30-60 mL/min:

• Dose: 1 gram intravenously every 24 hours 2
• Alternative acceptable regimen: 0.5-1 gram every 12-24 hours depending on infection severity 3

The standard dose of 1 gram twice daily used in patients with normal renal function must be reduced to prevent drug accumulation and neurotoxicity 1, 4.

Critical Safety Considerations

Neurotoxicity Risk

Monitor closely for mental status changes, encephalopathy, and myoclonus, as cefepime neurotoxicity is a serious adverse event in patients with renal impairment receiving excessive doses 1, 4. This syndrome includes:

• Altered mental status or confusion
• Myoclonus (involuntary muscle jerking)
• Seizures
• Encephalopathy

Neurotoxicity can occur even with "normal" renal function in some patients, making vigilant monitoring essential for all patients on cefepime 4.

Dose Adjustment Rationale

With declining renal function, cefepime elimination half-life increases substantially (from ~2 hours in normal function to potentially >20 hours in severe impairment), necessitating dose reduction to prevent toxic accumulation 5, 1.

Treatment Efficacy

The recommended reduced dose maintains excellent efficacy for UTI:

• Clinical cure rates of 94-97% for UTI with 1 gram dosing regimens 2
• Bacteriological eradication rates of 93-94% 3, 2
• Mean treatment duration: 8-10 days 3, 2

Monitoring Parameters

• Daily assessment for neurotoxicity signs (confusion, myoclonus, altered mental status) 1, 4
• Serial renal function monitoring (creatinine, BUN) during therapy 1
• Clinical response assessment at 3-5 days 3
• Consider EEG if neurotoxicity suspected 1

Additional Considerations for Elderly Patients

In this 71-year-old patient, be aware that:

• Fluoroquinolones should generally be avoided in elderly patients with comorbidities due to contraindications and adverse effects 6
• Polypharmacy and drug interactions require careful consideration in treatment selection 6
• Atypical UTI presentations are common in older adults 6