Cat · Felis catus · typical adult weight 2.50–7.00 kg
Fomepizole (4-MP) is dosed at 125 mg/kg IV Loading 125mg/kg, then 31.25mg/kg q12h x 3 doses in cats, per Connally HE, Thrall MA, Hamar DW. Safety and efficacy of high-dose fomepizole compared with ethanol as therapy for ethylene glycol intoxication in cats. J Vet Emerg Crit Care. 2010;20(2):191-206. doi:10.1111/j.1476-4431.2009.00492.x — Verified against Plumb's Veterinary Drug Handbook, 10th Ed, p.585 (2026-08-01).. Fomepizole (4-MP) is used in cats for Ethylene glycol toxicosis. Routes documented in cats: IV. A typical adult cat weighs 2.50–7.00 kg. ExoticRx lists 1 cited dose rule for Fomepizole (4-MP) in cats, drawn from published veterinary references. Verify against current literature before clinical use.
US trade names: Antizol-Vet
| Route | Dose | Frequency | Duration | Indication | Evidence | Source |
|---|---|---|---|---|---|---|
| IV | 125 mg/kg | Loading 125mg/kg, then 31.25mg/kg q12h x 3 doses | Higher dose required in cats; 4-dose protocol over 36 hours | Ethylene glycol toxicosis | Moderate | Connally HE, Thrall MA, Hamar DW. Safety and efficacy of high-dose fomepizole compared with ethanol as therapy for ethylene glycol intoxication in cats. J Vet Emerg Crit Care. 2010;20(2):191-206. doi:10.1111/j.1476-4431.2009.00492.x — Verified against Plumb's Veterinary Drug Handbook, 10th Ed, p.585 (2026-08-01). |
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These ranges are per kg. Enter your cat's weight to get the precise dose and draw-up volume — unit and concentration math done for you.
Competitive inhibitor of alcohol dehydrogenase, preventing metabolism of ethylene glycol to toxic metabolites (glycolaldehyde, glycolic acid, oxalate).
Most effective within 8-12 hours of ethylene glycol ingestion in dogs (3 hours in cats). Cats require higher doses. Very expensive but life-saving.
Species-specific contraindications and adverse-reaction reports for cats may differ from canine / feline reference data — consult the primary citations listed with each rule.
Fomepizole (4-MP) dose range in cats, with cited source references: IV 125 mg/kg Loading 125mg/kg, then 31.25mg/kg q12h x 3 doses. Reference ranges from cited sources — verify against current literature before clinical use.
Documented routes for Fomepizole (4-MP) in cats: IV.
Cited course lengths for Fomepizole (4-MP) in cats include: Higher dose required in cats; 4-dose protocol over 36 hours. Duration depends on the indication — match it to the specific dose rule in the table above.
Fomepizole (4-MP) is indicated in cats for: Ethylene glycol toxicosis.
These are general warnings for Fomepizole (4-MP) across species; consult the cat dosing table above for species-specific guidance. Most effective within 8-12 hours of ethylene glycol ingestion in dogs (3 hours in cats). Cats require higher doses. Very expensive but life-saving.
Why a species-specific page? Fomepizole (4-MP) pharmacokinetics differ across species: dose ranges, intervals, and route preferences are not interchangeable. Cross-extrapolation from canine doses is unsafe in cats — 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.