Cefepime
Cefepime is a **4th-generation cephalosporin** antibiotic with a broad spectrum of activity against both gram-positive and gram-negative pathogens. * **Structural Advantage:** It possesses a **zwitterionic structure** (having a net neutral charge), which allows it to rapidly penetrate the outer membrane porins of gram-negative bacteria. * **Beta-Lactamase Stability:** It is highly resistant to hydrolysis by many beta-lactamases, including AmpC beta-lactamases, and does not readily induce their production. * **Spectrum:** It offers excellent coverage against *Pseudomonas aeruginosa* and *Enterobacteriaceae* (similar to 3rd-generation agents like ceftazidime) while retaining robust activity against gram-positive aerobes like *Staphylococcus* and *Streptococcus* species. > **Clinical Pearl:** Due to its high cost, lack of oral formulation, and requirement for frequent dosing (short half-life), cefepime is typically reserved for critically ill hospitalized patients (such as neonatal foals or dogs with sepsis) where multi-drug resistant infections are suspected and other beta-lactams, aminoglycosides, or fluoroquinolones are ineffective or contraindicated.
Mechanism: Cefepime is a **bactericidal**, time-dependent antibiotic that works by disrupting bacterial cell wall synthesis. * **Target Binding:** It rapidly penetrates the bacterial cell envelope and binds with high affinity to specific **penicillin-binding proteins (PBPs)**, primarily PBP 3 and PBP 2. * **Inhibition:** Binding to PBPs inhibits the transpeptidation enzyme responsible for cross-linking peptidoglycan strands. * **Cell Lysis:** The lack of a structurally sound cell wall → activation of bacterial autolysins → **osmotic cell lysis** and bacterial death.
Dosing by species
- For susceptible infections in foals (gram-negative infections) · 11 mg/kg IV q8h · IV · q8h
- Neonates with poor aminoglycoside kinetics or documented multi-resistant infections · 11 mg/kg IV q8h · IV · q8h · Use has been limited primarily to neonates
- For susceptible infections · 40 mg/kg IV q6h · IV · q6h
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Routes of administration
Contraindications
- Hypersensitivity to cefepime or other cephalosporins
- Caution in patients with severe renal impairment (dosage adjustment required)
Adverse effects
- Loose stools or diarrhea
- Pain on IM injection
- Injection site inflammation
- Hypersensitivity reactions (rash, anaphylaxis)
- Neurologic effects (encephalopathy, seizures) in patients with renal dysfunction
Drug interactions
- Aminoglycosides · Potential for increased risk of nephrotoxicity; monitor renal function closely.
Monitoring
- Clinical efficacy (resolution of infection signs)
- Renal function (especially in patients with pre-existing renal insufficiency or when used concurrently with nephrotoxic drugs)
Overdose
No specific information is available for acute toxicity in veterinary patients. In humans with impaired renal function, inadvertent overdoses have led to **encephalopathy, seizures, and neuromuscular excitability**. Treatment should be supportive, and renal function must be monitored.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.