Antifreeze Poisoning: A Deadly Winter Danger
Ethylene glycol in antifreeze is sweet-tasting and deadly. Even small amounts cause irreversible kidney failure.
Antifreeze (ethylene glycol) poisoning is one of the most lethal toxicities in pets. The sweet taste attracts dogs and cats, and as little as 1 teaspoon per kilogram of body weight can be fatal. Early symptoms resemble drunkenness; later stages cause irreversible kidney failure. RVC provides emergency treatment for antifreeze poisoning. Call +853 6677 6611 IMMEDIATELY if you suspect exposure.
Key Points
- Ethylene glycol is sweet-tasting and attractive to pets
- As little as 1 tsp per kg can be fatal to dogs; even less for cats
- Stage 1 (30 min-12 hr): drunkenness, vomiting, excessive thirst
- Stage 2 (12-24 hr): apparent improvement as ethylene glycol is metabolized
- Stage 3 (24-72 hr): kidney failure, seizures, coma, death
- Antidote (fomepizole or ethanol) must be given within 8-12 hours
How Antifreeze Kills
Ethylene glycol itself is not highly toxic — the danger comes from its metabolites (breakdown products) produced by the liver. These metabolites: 1) Form calcium oxalate crystals that deposit in kidneys, blocking function. 2) Cause severe metabolic acidosis. 3) Directly damage kidney tubules. Once sufficient kidney damage occurs (usually 24-48 hours after ingestion), it is irreversible. Cats are more sensitive than dogs because they metabolize ethylene glycol faster.
Sources of Exposure
Common sources: radiator coolant/antifreeze (95% ethylene glycol), windshield de-icing fluid, brake fluid, HVAC system fluids, decorative snow globes, and some paints and solvents. Spills in garages, driveways, and parking lots are common exposure sites. Pets may lick spilled liquid from puddles, garage floors, or even their own paws after walking through it. In Macau, antifreeze use is lower than in cold climates, but imported vehicles and industrial use create exposure risk.
Symptoms by Stage
Stage 1 (30 minutes - 12 hours): vomiting, excessive thirst, frequent urination, ataxia (staggering like drunk), depression, and seizures. Stage 2 (12-24 hours): apparent improvement as ethylene glycol is metabolized — this is dangerously misleading. Stage 3 (24-72 hours in dogs; 12-24 hours in cats): severe kidney failure — vomiting, oral ulcers, extreme lethargy, coma, seizures, and death. By this stage, treatment is usually futile.
Emergency Treatment
If you suspect antifreeze ingestion, GO TO THE VET IMMEDIATELY — do not wait for symptoms. Time is critical. Treatment: antidote (fomepizole is preferred — inhibits alcohol dehydrogenase, preventing toxic metabolite formation). Must be given within 8-12 hours of ingestion for dogs; within 3 hours for cats. Alternative: intravenous ethanol (competes with ethylene glycol for metabolism). IV fluids, sodium bicarbonate for acidosis, and hemodialysis at specialty centers. Prevention: use propylene glycol-based antifreeze (less toxic), clean spills immediately, and keep all chemicals secure.
When to See a Vet Immediately
- Suspected ingestion of antifreeze, coolant, or de-icing fluid
- Drunkenness or staggering without alcohol exposure
- Vomiting with history of garage or driveway access
- Excessive thirst and urination after possible toxin exposure
- Any pet found near spilled automotive fluids
- NEVER wait for symptoms — treat immediately if exposure is possible
How RVC Can Help
Antifreeze poisoning is a critical emergency. RVC provides 24/7 emergency care. If you suspect exposure, come immediately or call +853 6677 6611. Time is everything.
This article is for educational purposes only and does not replace professional veterinary advice. If your pet is showing any symptoms, please contact Royal Veterinary Center immediately at +853 6677 6611.