Equine · Equus caballus · typical adult weight 350.00–700.00 kg
Metronidazole is dosed at 15–25 mg/kg PO q12h in horses, per Plumb's Veterinary Drug Handbook, 10th ed (2023, held copy; the original seed cited the 9th, which was never consulted) — Metronidazole, HORSES, printed p.876 (corpus PDF p.903): 'Metritis secondary to Bacteroides fragilis (extra-label): 15 - 25 mg/kg PO every 12 hours' — SOURCE EDITION: Plumb's Veterinary Drug Handbook — ISBN 9781394172207, https://openlibrary.org/isbn/9781394172207. Metronidazole is used in horses for Anaerobic infections, Clostridial colitis, Metritis secondary to Bacteroides fragilis. Routes documented in horses: PO. A typical adult horse weighs 350.00–700.00 kg. ExoticRx lists 2 cited dose rules for Metronidazole in horses, drawn from published veterinary references. Verify against current literature before clinical use.
US trade names: Flagyl
| Route | Dose | Frequency | Duration | Indication | Evidence | Source |
|---|---|---|---|---|---|---|
| PO | 15–25 mg/kg | q12h | 7-10 days | Anaerobic infections, Clostridial colitis | Moderate | Plumb's Veterinary Drug Handbook, 10th ed (2023, held copy; the original seed cited the 9th, which was never consulted) — Metronidazole, HORSES, printed p.876 (corpus PDF p.903): 'Metritis secondary to Bacteroides fragilis (extra-label): 15 - 25 mg/kg PO every 12 hours' — SOURCE EDITION: Plumb's Veterinary Drug Handbook — ISBN 9781394172207, https://openlibrary.org/isbn/9781394172207 |
| PO | 15–25 mg/kg | q12h | 7-14 days | Metritis secondary to Bacteroides fragilis | Strong | Plumb's Veterinary Drug Handbook, 10th ed (2023, held copy; the original seed cited the 9th, which was never consulted) — Metronidazole, HORSES, printed p.876 (corpus PDF p.903): 'Metritis secondary to Bacteroides fragilis (extra-label): 15 - 25 mg/kg PO every 12 hours' — SOURCE EDITION: Plumb's Veterinary Drug Handbook — ISBN 9781394172207, https://openlibrary.org/isbn/9781394172207 — Plumb's Veterinary Drug Handbook, 10th ed (held), Metronidazole monograph, printed p.876 (corpus PDF p.903), HORSES: "Metritis secondary to Bacteroides fragilis (extra-label): 15 - 25 mg/kg PO every 12 hours." [INDICATION CORRECTED 2026-08-12, two readers — the equine clostridial enterocolitis figure on printed p.875 is 15 mg/kg PO every 8 to 12 hours, not 15-25.] |
Every held source for this drug and species, as printed. Where they differ, both are shown — the choice is yours, not ours.
| Dose (mg/kg) | Route | Source | As printed |
|---|---|---|---|
| 10 | PO | Papich Saunders Handbook of Veterinary Drugs, 4th edp.554 | • Treatment of anaerobic and protozoal infections: 10 mg/kg q12h PO. Note: |
| 15–20 | — | Papich Saunders Handbook of Veterinary Drugs, 4th edp.554 | Some clinicians have used higher doses (up to 15-20 mg/kg q6h), but at these |
| 10–15 | IV | Papich Saunders Handbook of Veterinary Drugs, 4th edp.554 | • Foals: 10-15 mg/kg IV or PO q12h. |
Figures are transcribed from the cited page or table of each held edition and are shown for reference only. They are not dose recommendations, they do not feed the calculator, and none has been reviewed by a veterinarian.
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Disrupts DNA structure in anaerobic organisms via reduction of nitro group, forming cytotoxic intermediates.
Neurotoxicity at high doses or prolonged use (ataxia, seizures). Avoid in pregnant animals. Hepatotoxic at high doses.
Species-specific contraindications and adverse-reaction reports for horses may differ from canine / feline reference data — consult the primary citations listed with each rule.
Metronidazole dose ranges in horses, with cited source references: PO 15–25 mg/kg q12h; PO 15–25 mg/kg q12h. Reference ranges from cited sources — verify against current literature before clinical use.
Documented routes for Metronidazole in horses: PO.
Cited course lengths for Metronidazole in horses include: 7-10 days; 7-14 days. Duration depends on the indication — match it to the specific dose rule in the table above.
Metronidazole is indicated in horses for: Anaerobic infections, Clostridial colitis, Metritis secondary to Bacteroides fragilis.
These are general warnings for Metronidazole across species; consult the horse dosing table above for species-specific guidance. Neurotoxicity at high doses or prolonged use (ataxia, seizures). Avoid in pregnant animals. Hepatotoxic at high doses.
Why a species-specific page? Metronidazole pharmacokinetics differ across species: dose ranges, intervals, and route preferences are not interchangeable. Cross-extrapolation from canine doses is unsafe in horses — the rules above are the citations specific to this species, not generic recommendations.
Sourced from published veterinary references; awaiting credentialed clinical reviewer. See our editorial process. Reference only — not veterinary advice.