Vancomycin

Vancomycin is a glycopeptide antibacterial with activity directed mainly against susceptible gram-positive organisms. Veterinary applications are uncommon and involve selected serious resistant infections or localized treatment plans. Parenteral and oral administration have different clinical roles because oral drug is poorly absorbed and acts mainly within the gastrointestinal lumen.

Group

Glycopeptide antibacterial

Mechanism of Action

Vancomycin binds the D-alanyl-D-alanine terminus of susceptible bacterial cell-wall precursors. This obstructs incorporation and cross-linking of peptidoglycan, impairing cell-wall formation and producing antibacterial activity. The outer membrane of gram-negative organisms limits access to this target. Parenteral delivery provides systemic exposure, whereas oral drug remaining in the gut targets susceptible intestinal organisms.

Dose Rates

Dogs

Use / stage	Dose	Route	Schedule	Instructions
Resistant gram-positive infection	15 mg/kg	IV	Every 6–8 h	Start every 8 hours; if exposure inadequate, shorten to 6 hours using monitoring. Administer by slow infusion.
Antibacterial infusion — Loading	3.5 mg/kg	IV	Once
Antibacterial infusion — Maintenance	1.5 mg/kg/hour	IV	Continuous	Dilute in 5% dextrose.
Clostridioides difficile enterocolitis	10–20 mg/kg	PO	Every 6 h	Up to 7 days; Reported 5-7 days; oral drug acts locally and is not systemic treatment.
Skin urinary or soft tissue infection	10–20 mg/kg	IV	Every 12 h	Up to 10 days; Reported 7-10 days; slow infusion.

Cats

Use / stage	Dose	Route	Schedule	Instructions
Resistant gram-positive infection	12–15 mg/kg	IV	Every 8 h	Slow IV infusion.
Resistant gram-positive infection	15 mg/kg	IV	Every 6–8 h	Over 30-60 minutes; therapeutic and renal monitoring.

Horses

Use / stage	Dose	Route	Schedule	Instructions
Resistant gram-positive infection	4.3–7.5 mg/kg	IV	Every 8 h	Infuse over 1 hour.

Indications

Specialist treatment of serious vancomycin-susceptible resistant gram-positive infections in veterinary patients, including selected staphylococcal or enterococcal infections.
Selected regional treatment of susceptible orthopedic or deep-tissue infections under a specialist antimicrobial plan.
Specialist oral treatment of selected Clostridioides difficile-associated enterocolitis, with limited veterinary clinical evidence.

Contraindications

Avoid rapid IV injection; IM and SC are painful and inappropriate for routine systemic therapy.

Interactions

Incompatible with many co-infused medicines; other nephrotoxins increase renal risk.

Adverse effects

Renal injury, infusion reactions and possible neutropenia.

Toxicity

Overdose increases renal and auditory toxicity risk. Oral absorption may increase with severe intestinal inflammation; monitor renal function and systemic exposure.

Preparations

Preparation	Form	Strength	Route
Vancomycin 500 mg vial	Injection	500 mg / vial	IV
Vancomycin 1000 mg vial	Injection	1000 mg / vial	IV
Vancomycin 5000 mg vial	Injection	5000 mg / vial	IV
Vancomycin 10000 mg vial	Injection	10000 mg / vial	IV

Monitoring and Administration

Use slow IV infusion and therapeutic drug monitoring; assess creatinine/BUN and urinalysis. Reported proposes AUC/MIC above 400 or individualized trough monitoring; veterinary targets are less established than human targets.

Use a separate compatible infusion solution; reconstituted product stability depends on the actual formulation.

Equine regional limb perfusion is described as 300 mg diluted to 0.5%; this is a local tourniquet-based procedure, not a systemic IV dose.

Canine intermittent infusion: deliver over 30-60 minutes; the reported guidance also describes an approximately 10 mg/min maximum practical administration rate. Avoid rapid bolus injection.

500-mg and 1-g injectable vials are reconstituted with 10 and 20 mL sterile water respectively, then further diluted in at least 100 or 200 mL compatible infusion fluid before use. These are preparation instructions; added diluent volume is not assumed to equal exact final volume for automatic mL calculation.