Vancomycin
**Vancomycin** is a powerful, bactericidal glycopeptide antibiotic traditionally considered a "drug of last resort" in both human and veterinary medicine. * **Clinical Role:** It is strictly reserved for severe, life-threatening infections caused by multi-drug resistant gram-positive bacteria, such as **Methicillin-Resistant *Staphylococcus aureus* (MRSA)**, **Methicillin-Resistant *Staphylococcus pseudintermedius* (MRSP)**, and multidrug-resistant *Enterococcus* species. * **Administration:** For systemic infections, it **must** be administered intravenously (IV) as a slow infusion. Subcutaneous (SC) or intramuscular (IM) injections are strictly contraindicated due to severe tissue necrosis and pain. * **Oral Use:** Because vancomycin is not absorbed through the gastrointestinal tract, oral administration is exclusively used to treat severe, localized enteric infections, specifically **pseudomembranous colitis caused by *Clostridium difficile***. > **Clinical Pearl:** Due to the critical importance of vancomycin in treating life-threatening human infections, its use in veterinary medicine is highly controversial and should only be considered when culture and susceptibility testing confirm no other viable antibiotic options exist.
Mecanismo: Vancomycin exerts its bactericidal effect primarily by inhibiting bacterial cell wall synthesis. * **Target Binding:** It binds tightly and non-covalently to the **D-alanyl-D-alanine** terminus of cell wall precursor units. * **Inhibition:** This massive steric hindrance prevents the enzymes (transglycosylases and transpeptidases) from incorporating the precursors into the growing peptidoglycan matrix → **inhibition of cell wall cross-linking**. * **Secondary Mechanisms:** It also alters bacterial cell-membrane permeability and interferes with RNA synthesis, making resistance more difficult to develop. * **Spectrum:** Activity is strictly limited to **gram-positive** organisms (staphylococci, streptococci, enterococci, *Clostridium*, *Listeria*). It is bactericidal against most susceptible bacteria but generally bacteriostatic against enterococci.
Dosificación por especie
- Confirmed bacteremia/septicemia for enterococci or staphylococci resistant to other commonly used antibiotics · 15 mg/kg IV over 30-60 minutes · IV · q6-8h
- Serious infections · 15 mg/kg IV over 30-60 minutes · IV · q6h · For successful therapy, an aminoglycoside such as gentamicin or amikacin should also be administered.
- Confirmed bacteremia/septicemia for enterococci or staphylococci resistant to other commonly used antibiotics · 15 mg/kg IV over 30-60 minutes · IV · q6-8h
- Serious infections · 15 mg/kg IV over 30-60 minutes · IV · q6h · For successful therapy, an aminoglycoside such as gentamicin or amikacin should also be administered.
- C. difficile enterocolitis · 10-20 mg/kg PO · PO · q6h · 5-7 days · Oral vancomycin is not appreciably absorbed and is only effective for susceptible enteric infections.
- Skin, urinary, soft tissue infections · 10-20 mg/kg IV · IV · q12h · 7-10 days
- Systemic infections, bacteremia · 15 mg/kg IV · IV · q6h · 10 days
Las dosis son una referencia clínica para veterinarios colegiados. Confirme siempre con la ficha técnica vigente y el paciente individual.
Vías de administración
Contraindicaciones
- Infections susceptible to other, lower-tier antibiotics
- Intramuscular (IM), Subcutaneous (SC), or Intraperitoneal (IP) administration
- Rapid IV bolus administration
Efectos adversos
- Nephrotoxicity (especially with concurrent nephrotoxic drugs)
- Ototoxicity (hearing loss/vestibular signs)
- Thrombophlebitis (if given IV too rapidly)
- Severe hypotension or cardiac arrest (rare, associated with rapid IV bolus)
- Severe tissue damage and pain (if given IM, SC, or IP)
- Nausea and inappetence (with oral administration)
- Reversible neutropenia (with high/prolonged dosing)
- Hypersensitivity/dermatologic reactions (known in humans as 'Red Man Syndrome' due to histamine release)
Interacciones farmacológicas
- Aminoglycosides (e.g., gentamicin, amikacin) · Synergistic antibacterial effect, but significantly increases the risk of ototoxicity and nephrotoxicity. Enhanced monitoring is required.
- Anesthetic agents · May cause erythema and histamine-like flushing (reported in human pediatric patients).
- Nephrotoxic drugs (e.g., amphotericin B, cisplatin) · Increased risk of severe nephrotoxicity; use together with extreme caution.
Monitorización
- Renal function (BUN, Creatinine, Urinalysis) at baseline and periodically during treatment
- Vancomycin serum trough levels (maintain above 5 mcg/mL; some specialists recommend 10-15 mcg/mL)
- Periodic Complete Blood Count (CBC) if therapy is prolonged (to monitor for neutropenia)
- Hearing and vestibular function (clinical observation)
Sobredosis
Patients with severe colitis taking an oral overdose could potentially absorb enough drug to cause systemic adverse effects. Intravenous overdoses significantly increase the risk of **ototoxicity** (hearing/balance damage) and **nephrotoxicity** (kidney damage). * **Toxicity Data:** The IV LD50 in mice is 400 mg/kg and in rats is 319 mg/kg. * **Treatment:** Treatment is primarily supportive care. Hemodialysis does not appear to remove the drug in significant amounts.
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.