# Vancomycin: veterinary dose and monograph

> Vancomycin is a veterinary antibiotic. Glycopeptide antibiotic and a critical LAST-RESORT agent for serious Gram-positive infections resistant to other drugs — notably methicillin-resistant staphylococci (MRSA/MRSP) and resistant enterococci. Indications include methicillin-resistant Staphylococcus (MRSA/MRSP) infection with no other option; resistant enterococcal infection; serious resistant Gram-positive sepsis (culture-confirmed). This monograph lists 5 reference doses for dogs, cats and horses, each with route, frequency and source.

Source: https://vetmasterji.com/drugs/vancomycin · Last reviewed: 2026-10-01

## At a glance

- **Drug class:** Antibiotic
- **Also known as:** Vancocin, Vancomab, Vanlid
- **Species with doses:** Dogs, Cats and Horses
- **General dose range:** 15 mg/kg IV q6–8h — check the species tables for the indication
- **Routes:** IV, PO
- **Last reviewed:** 1 October 2026

## Indications

- Methicillin-resistant Staphylococcus (MRSA/MRSP) infection with no other option
- Resistant enterococcal infection
- Serious resistant Gram-positive sepsis (culture-confirmed)
- Oral: refractory C. difficile / antibiotic-associated colitis (gut-local)

## Vancomycin dose by species

Doses are per administration unless stated. mg/kg doses scale with body weight; per-animal, per-quarter and infusion-rate doses are shown as the reference writes them.

### Dogs

*Vancomycin doses for dogs*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| Resistant Gram-positive infection (IV) | 15 mg/kg | IV | q6–8h | — |
| Refractory C. difficile colitis (oral, gut-local) | 10–20 mg/kg | PO | q6h | 5–7 days |
| Constant-rate infusion | 1.5 mg/kg/h | IV | CRI after 3.5 mg/kg load | — |

- Resistant Gram-positive infection (IV): Papich 5e: 15 mg/kg q6–8h IV infusion (start q8h, shorten to q6h by monitoring). Plumb’s p.1160: bacteraemia 15 mg/kg IV over 30–60 min q6–8h (Ford 2005); skin/urinary/soft tissue 10–20 mg/kg IV q12h for 7–10 days (Greene). Dilute (≥100 mL per 500 mg); reserve for MRSA/MRSP and resistant enterococci.
- Refractory C. difficile colitis (oral, gut-local): Plumb’s p.1160 (Greene 2006): C. difficile enterocolitis 10–20 mg/kg PO q6h for 5–7 days. Not absorbed orally — gut lumen only.
- Constant-rate infusion: Papich 5e: loading dose 3.5 mg/kg, then 1.5 mg/kg/h in 5% dextrose.

### Cats

*Vancomycin doses for cats*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| Resistant Gram-positive infection (IV) | 12–15 mg/kg | IV | q8h | — |

- Resistant Gram-positive infection (IV): Papich 5e: 12–15 mg/kg q8h IV infusion. Plumb’s p.1160: 15 mg/kg IV over 30–60 min q6–8h (Ford 2005; Papich 2003 — combine with an aminoglycoside for serious infections). Reserve for confirmed resistant enterococci/staphylococci; monitor renal function and trough levels.

### Horses

*Vancomycin doses for horses*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| Resistant Gram-positive infection | 4.3–7.5 mg/kg | IV | q8h (infuse over 1 h) | — |

- Resistant Gram-positive infection: Papich 5e: 4.3–7.5 mg/kg q8h IV over 1 hour; regional limb perfusion 300 mg as a 0.5% solution.

## Contraindications

Rapid IV infusion (causes "red man" syndrome — histamine-mediated flushing/hypotension; infuse over ≥60 min). Renal impairment (nephrotoxic — adjust by levels). Concurrent nephro-/ototoxins. Routine use (reserve agent). Known hypersensitivity.

## Adverse effects

- "Red man" syndrome (flushing, hypotension) with rapid infusion
- Nephrotoxicity (dose/level-related)
- Ototoxicity (high levels, prolonged use)
- Phlebitis, fever, neutropenia (prolonged use)

## Drug interactions

- Aminoglycosides / amphotericin B / other nephrotoxins: additive nephro-/ototoxicity
- Anaesthetics: increased frequency of red-man-type reactions
- Neuromuscular blockers: enhanced blockade

## Pregnancy and lactation

Limited veterinary data; reserved for life-threatening resistant infection where benefit outweighs risk.

## Monitoring

- Serum trough levels (therapeutic drug monitoring) where available
- Renal function (creatinine) frequently
- Infusion rate / red-man reaction
- Hearing (prolonged therapy); culture confirming a no-alternative resistant organism

## Toxicity and overdose

Dose-/level-dependent nephrotoxicity and ototoxicity are the key toxicities; rapid infusion provokes red-man syndrome (flushing, hypotension). Therapeutic drug monitoring (trough levels) is ideal to balance efficacy and toxicity.

Management: No specific antidote. Slow/stop the infusion for red-man syndrome and give antihistamine ± fluids. For toxicity: discontinue, support renal function with fluids, monitor hearing/renal values; some removal by high-flux haemodialysis/haemofiltration.

## Clinical pearls

- Reserve of last resort — only for culture-confirmed MRSA/MRSP or resistant enterococci with NO alternative (One-Health stewardship)
- Infuse slowly (≥1 h): fast IV causes red-man syndrome (flushing, hypotension)
- IV for systemic infection; ORAL vancomycin treats only gut C. difficile (it is not absorbed)
- Monitor renal function and, ideally, trough levels to stay effective without toxicity
- Never use casually — veterinary vancomycin use is ethically and epidemiologically sensitive

## Mechanism of action

Binds the D-alanyl-D-alanine terminus of peptidoglycan precursors, sterically blocking transglycosylation/transpeptidation and halting bacterial cell-wall synthesis — bactericidal against Gram-positives (its large molecule cannot cross the Gram-negative outer membrane, hence no Gram-negative activity). Resistance (e.g. VRE) arises from altered D-Ala-D-Lac termini.

## Formulations and products

- Injection 500 mg vial (reconstitute)
- Injection 1 g vial (reconstitute)
- Vancocin — 500 mg / 1 g vial, Injection (reconstitute) (human-label)
- Vanlid — 250 mg capsule; 500 mg / 1 g vial, Capsule / injection (human-label)

## Storage

Powder vial: 15–30 °C. Reconstituted/diluted solution: refrigerate and use within ~24 h (per label). Infuse diluted (never as a bolus).

## Before you use this dose

> **Caution:** Reference doses for veterinary professionals. Confirm the dose against the product label, the patient’s condition, current guidance and local regulations before use; the attending veterinarian remains responsible for every clinical decision.

## Other antibiotics

- [Tobramycin](https://vetmasterji.com/drugs/tobramycin)
- [Trimethoprim / Sulfadiazine (TMP-Sulfa)](https://vetmasterji.com/drugs/tmp-sulfa)
- [Tulathromycin](https://vetmasterji.com/drugs/tulathromycin)
- [Tylvalosin](https://vetmasterji.com/drugs/tylvalosin)

## Frequently asked questions

### What is the dose of Vancomycin for dogs?

Reference doses for Vancomycin in dogs: 15 mg/kg IV q6–8h (Resistant Gram-positive infection (IV)); 10–20 mg/kg PO q6h for 5–7 days (Refractory C. difficile colitis (oral, gut-local)); 1.5 mg/kg/h IV CRI after 3.5 mg/kg load (Constant-rate infusion). Confirm against the label and the patient before use.

### What is the dose of Vancomycin for cats?

Reference doses for Vancomycin in cats: 12–15 mg/kg IV q8h (Resistant Gram-positive infection (IV)). Confirm against the label and the patient before use.

### What is the dose of Vancomycin for horses?

Reference doses for Vancomycin in horses: 4.3–7.5 mg/kg IV q8h (infuse over 1 h) (Resistant Gram-positive infection). Confirm against the label and the patient before use.

### When should Vancomycin not be used?

Rapid IV infusion (causes "red man" syndrome — histamine-mediated flushing/hypotension; infuse over ≥60 min). Renal impairment (nephrotoxic — adjust by levels). Concurrent nephro-/ototoxins. Routine use (reserve agent). Known hypersensitivity.

### What are the side effects of Vancomycin in animals?

"Red man" syndrome (flushing, hypotension) with rapid infusion; Nephrotoxicity (dose/level-related); Ototoxicity (high levels, prolonged use); Phlebitis, fever, neutropenia (prolonged use).

## Sources

- Plumb's Veterinary Drug Handbook
- Merck Veterinary Manual, 11th edition
- Papich, Papich Handbook of Veterinary Drugs, 5th edition

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VetMasterJi is a clinical decision-support and education platform for veterinary professionals and students. It does not provide veterinary advice, diagnosis or treatment for specific animals. All drug doses, calculators and differentials are references that must be independently verified before clinical use; the attending registered veterinarian remains solely responsible for every clinical decision.