Cefotetan
Cefotetan is a **2nd-generation cephalosporin** (specifically a cephamycin) with an extended spectrum of activity against anaerobic bacteria (such as *Bacteroides* spp.) and enteric Gram-negative rods (such as *E. coli*). It is structurally and pharmacologically similar to cefoxitin but boasts a more favorable pharmacokinetic profile, allowing for less frequent dosing intervals in small animals. **Clinical Pearls:** - Cefotetan contains an **N-methylthiotetrazole (NMTT) side chain** (similar to cefoperazone). This specific structural feature can interfere with vitamin K metabolism, potentially leading to hypoprothrombinemia (bleeding tendencies), and can cause disulfiram-like reactions if exposed to alcohol. - It is highly effective against many anaerobes and is often utilized for serious soft tissue infections, sepsis, or intra-abdominal infections.
Mecanismo: Cefotetan is a **bactericidal** time-dependent antibiotic. - It binds to specific **Penicillin-Binding Proteins (PBPs)** located inside the bacterial cell wall. - Binding → inhibition of the third and final stage of bacterial cell wall synthesis (mucopeptide/peptidoglycan cross-linking). - This leads to weakened cell walls → cell lysis and death mediated by bacterial autolysins. - As a cephamycin, it is highly resistant to degradation by many beta-lactamases produced by Gram-negative and anaerobic bacteria.
Dosificación por especie
- Sepsis · 30 mg/kg q5-8h IV · IV · q5-8h
- Susceptible infections · 30 mg/kg SC q12h · SC · q12h
- Soft tissue infections · 30 mg/kg SC q12h · SC · q12h · 7 days or less
- Bacteremia, sepsis · 30 mg/kg IV, SC q8h · IV, SC · q8h · as long as required
Las dosis son una referencia clínica para médicos veterinarios. Confirme siempre con la información vigente del producto y el paciente individual.
Vías de administración
Contraindicaciones
- Known hypersensitivity to cephamycins or cephalosporins
- Caution in patients with documented hypersensitivity to penicillins or other beta-lactams (cross-reactivity possible)
- Caution in patients with severe renal dysfunction (dose interval adjustment may be required)
Efectos adversos
- Pain at IM injection site
- Thrombophlebitis (IV administration)
- Hypersensitivity reactions (rash, fever, anaphylaxis)
- Bleeding tendencies (hypoprothrombinemia due to NMTT side chain)
- Gastrointestinal flora alteration (diarrhea, superinfections)
- Rarely: nephrotoxicity, neurotoxicity, neutropenia, thrombocytopenia at high doses
Interacciones farmacológicas
- Alcohol · Potential for a disulfiram-like reaction (vomiting, etc.) due to the NMTT side chain.
- Aminoglycosides · Potential additive nephrotoxicity; do not mix together in the same syringe/fluid bag (administer separately). May have synergistic antibacterial activity.
- Nephrotoxic drugs (e.g., Amphotericin B) · Potential additive nephrotoxicity.
Monitoreo
- Clinical efficacy (resolution of infection)
- Renal function in patients with pre-existing renal disease
- Signs of bleeding or coagulopathy (due to NMTT side chain)
Sobredosis
Massive or chronic overdoses are required to cause significant adverse effects. **Seizures** are possible with extreme beta-lactam overdoses, particularly in patients with renal impairment. Treatment is supportive and symptomatic.
La referencia de fármacos de VetSheet está destinada a médicos veterinarios como apoyo a la decisión clínica; no sustituye el juicio profesional ni la información vigente del fabricante.