The critical species difference is the antidote: fomepizole (4-methylpyrazole, 4-MP) is the first-line antidote in dogs at a standard canine protocol, while cats require a substantially higher dose of 4-MP, and the treatment window is 8 hours post-ingestion for dogs.
The treatment window is 8 hours from ingestion in dogs — dogs treated within this window carry a good prognosis, while delays are associated with high mortality.Journal of the… The same 8-hour window applies broadly to both species, as adequate treatment must be initiated within 8 hours of ingestion to prevent irreversible acute renal failure.Schweizer Archi…
In cats, 4-MP is dosed at 125 mg/kg IV as the initial dose, followed by 31.25 mg/kg IV at 12, 24, and 36 hours. This regimen is safe and effective for naturally occurring ethylene glycol (EG) toxicity in cats, with all treated cats surviving to discharge in reported cases.Journal of Vete… Increased bicarbonate concentrations are observed after IV 4-MP administration in cats, consistent with correction of metabolic acidosis.Journal of Vete…
The minimum lethal dose differs substantially between species. The minimum lethal dose of undiluted EG is 1.5 mL/kg for cats and 4.4–6.6 mL/kg for dogs, making cats significantly more susceptible.Journal of the… The case fatality rate is 78%–96% for cats and 44%–70% for dogs.Journal of the…
Hemodialysis is an additional treatment option when antidote therapy alone is insufficient, as it removes both the parent compound and toxic metabolites.Schweizer Archi… This is particularly relevant when presentation is delayed beyond the antidote window or when oligoanuric renal failure has already developed.Schweizer Archi…
Supportive care targets metabolic acidosis and renal failure — EG metabolites cause severe metabolic acidosis and renal tubular epithelial damage, and approximately 50% of ingested EG is excreted unchanged by the kidneys within the first hours, making early fluid diuresis relevant alongside antidote therapy.MSD Vet Manuals
A positive whole-blood EG test kit result requires clinical correlation. The Catachem quantitative kit reads higher than gas chromatography–mass spectrometry (GC-MS) values across all samples (serum bias +8.48 mg/dL, plasma bias +7.32 mg/dL), meaning some animals may receive treatment unnecessarily; however, animals at or above the published lethal serum concentration will be reliably identified.Journal of Vete… Additionally, choline chloride toxicosis has been documented to cause false-positive whole-blood EG test results in cats with no known antifreeze exposure, and should be considered as a differential when exposure history is absent.Topics in Compa…
| Species | Antidote | Initial Dose | Subsequent Doses | Treatment Window | Lethal Dose (undiluted EG) |
|---|---|---|---|---|---|
| Cat | 4-MP (fomepizole) IV | 125 mg/kg | 31.25 mg/kg at 12, 24, 36 h | ≤8 h from ingestion | 1.5 mL/kg |
| Dog | 4-MP (fomepizole) IV | Not specified in sources | Not specified in sources | ≤8 h from ingestion | 4.4–6.6 mL/kg |
Note: The specific canine 4-MP dosing protocol does not appear in the provided sources; the veterinary literature should be consulted for the standard canine fomepizole regimen.
Would you like guidance on interpreting renal ultrasonographic findings — specifically the hyperechoic cortex and medullary rim sign — to help stage severity and guide hemodialysis decisions?