Equine · Equus caballus · typical adult weight 350.00–700.00 kg
Phenylbutazone is dosed at 4.4 mg/kg IV q12h in horses, per Coleman MC. Laminitis. In: Smith BP, Van Metre DC, Pusterla N, eds. Large Animal Internal Medicine. 6th ed. St. Louis, MO: Elsevier; 2020:1235-1238. — Verified against Plumb's Veterinary Drug Handbook, 10th Ed, p.1042 (2026-08-01).. Phenylbutazone is used in horses for Acute musculoskeletal pain, Musculoskeletal pain, laminitis. Routes documented in horses: IV, PO. A typical adult horse weighs 350.00–700.00 kg. ExoticRx lists 2 cited dose rules for Phenylbutazone in horses, drawn from published veterinary references. Verify against current literature before clinical use.
US trade names: Butazolidin
| Route | Dose | Frequency | Duration | Indication | Evidence | Source |
|---|---|---|---|---|---|---|
| IV | 4.4 mg/kg | q12h | Switch to oral ASAP | Acute musculoskeletal pain | Strong | Coleman MC. Laminitis. In: Smith BP, Van Metre DC, Pusterla N, eds. Large Animal Internal Medicine. 6th ed. St. Louis, MO: Elsevier; 2020:1235-1238. — Verified against Plumb's Veterinary Drug Handbook, 10th Ed, p.1042 (2026-08-01). |
| PO | 4.4 mg/kg | q12h | Use lowest effective dose | Musculoskeletal pain, laminitis | Strong | Appendix 3 - Drug doses and intervals for horses and ruminants. In: Constable PD, Hinchcliff KW, Done SH, Grünberg W, eds. Veterinary Medicine. 11th ed.: WB Saunders; 2017:2220-2231. — Verified against Plumb's Veterinary Drug Handbook, 10th Ed, p.1042 (2026-08-01). |
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These ranges are per kg. Enter your horse's weight to get the precise dose and draw-up volume — unit and concentration math done for you.
Non-selective COX inhibitor with potent anti-inflammatory and analgesic properties.
High toxicity in dogs (bone marrow aplasia, GI ulceration). Primarily used in horses and dogs. NEVER use in cats. Perivascular injection causes severe tissue necrosis.
Species-specific contraindications and adverse-reaction reports for horses may differ from canine / feline reference data — consult the primary citations listed with each rule.
Phenylbutazone dose ranges in horses, with cited source references: IV 4.4 mg/kg q12h; PO 4.4 mg/kg q12h. Reference ranges from cited sources — verify against current literature before clinical use.
Documented routes for Phenylbutazone in horses: IV, PO.
Cited course lengths for Phenylbutazone in horses include: Switch to oral ASAP; Use lowest effective dose. Duration depends on the indication — match it to the specific dose rule in the table above.
Phenylbutazone is indicated in horses for: Acute musculoskeletal pain, Musculoskeletal pain, laminitis.
These are general warnings for Phenylbutazone across species; consult the horse dosing table above for species-specific guidance. High toxicity in dogs (bone marrow aplasia, GI ulceration). Primarily used in horses and dogs. NEVER use in cats. Perivascular injection causes severe tissue necrosis.
Why a species-specific page? Phenylbutazone 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.