Cefaclor
Cefaclor is an oral **second-generation cephalosporin** antibiotic. It shares a similar overall spectrum of activity with first-generation cephalosporins (such as cephalexin) but offers enhanced activity against certain gram-negative bacteria, including strains of *E. coli*, *Klebsiella pneumoniae*, and *Proteus mirabilis*. **Clinical Pearl:** While there is limited clinical experience with cefaclor in veterinary medicine, it serves as a potentially useful alternative when an oral cephalosporin is desired to treat bacterial infections that are resistant to first-generation cephalosporins but remain susceptible to cefaclor based on culture and sensitivity testing.
Mecanismo: Cefaclor is a **bactericidal** beta-lactam 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 (peptidoglycan cross-linking). * Defective cell wall → Cell lysis mediated by bacterial cell wall autolytic enzymes (autolysins). It possesses slightly better stability against certain beta-lactamases produced by gram-negative organisms compared to first-generation cephalosporins.
Dosificación por especie
- Skin or soft tissue infections · 7 mg/kg PO q8h · PO · q8h · 21-30 days
- Systemic, lower respiratory tract infections · 10-13 mg/kg PO q8h · PO · q8h · 14 days · Maximum daily dose is 1 gram.
- Skin or soft tissue infections · 7 mg/kg PO q8h · PO · q8h · 21-30 days
- Systemic, lower respiratory tract infections · 10-13 mg/kg PO q8h · PO · q8h · 14 days · Maximum daily dose is 1 gram.
Las dosis son una referencia clínica para veterinarios colegiados. Confirme siempre con la ficha técnica vigente y el paciente individual.
Vías de administración
Contraindicaciones
- Known hypersensitivity to cephalosporins
- Use with caution in patients with documented penicillin allergy (potential cross-reactivity)
- Severe renal impairment (requires dosage adjustment)
Efectos adversos
- Nausea
- Diarrhea
- Hypersensitivity reactions (including anaphylaxis)
- Serum-sickness-like reactions
- Erythema multiforme (rare)
- Rash
- Transient increases in liver enzymes
- Transient increases in BUN and serum creatinine
Interacciones farmacológicas
- Antacids (magnesium or aluminum-containing) · Reduces extent of absorption of extended-release cefaclor tablets
- Probenecid · Reduced renal excretion of cefaclor
- Warfarin · Rare reports of increased anticoagulant effect
Monitorización
- Clinical efficacy (resolution of infection)
- Renal function in patients with pre-existing renal insufficiency
Sobredosis
Cefaclor appears quite safe in dogs. * **Chronic high doses:** Dogs given daily PO doses of 200 mg/kg/day for 30 days developed soft stools, occasional emesis, and transient moderate decreases in hemoglobin. * **Massive chronic doses:** One dog given 400 mg/kg/day for one year developed a reversible thrombocytopenia.
La referencia de fármacos de VetSheet está destinada a veterinarios colegiados como apoyo a la decisión clínica, no sustituye el juicio profesional ni la ficha técnica vigente del fabricante.