Pharmacodynamics of cefepime

Area of Science:

• Microbiology
• Pharmacology
• Infectious Diseases

Background:

• Cefepime is a fourth-generation cephalosporin antibiotic.
• Understanding its efficacy against clinical isolates and its pharmacokinetic profile is crucial for optimizing treatment regimens.

Purpose of the Study:

• To evaluate the in vitro microbiological activity of cefepime.
• To assess the pharmacokinetic properties of cefepime in patients.
• To compare cefepime's pharmacodynamic profile with existing cephalosporins.

Main Methods:

• In vitro susceptibility testing of 232 clinical isolates against cefepime.
• Pharmacokinetic evaluation in six patients receiving 1g of cefepime every 12 hours.
• Calculation of an Intensity Index integrating drug concentration, duration, and minimum inhibitory concentration (MIC).

Main Results:

• Cefepime demonstrated low MIC90 values (≤0.25 mg/l) for Enterobacteriaceae and streptococci, 1 mg/l for Staphylococcus aureus, and 8 mg/l for Pseudomonas aeruginosa.
• Mean serum concentrations were 62.5 mg/l at end infusion and 1.1 mg/l at 12 hours, with an elimination half-life of 2.72 hours.
• Cefepime showed comparable or superior Intensity Index values to other cephalosporins against Gram-positive and Gram-negative bacteria.

Conclusions:

• Cefepime at 1g every 12 hours likely achieves inhibitory serum concentrations for most common Enterobacteriaceae, streptococci, and S. aureus.
• Higher doses or more frequent administration of cefepime may be required for certain Pseudomonas aeruginosa infections.
• The study supports cefepime's efficacy and provides a basis for optimizing its clinical use.