TL;DR: Antifreeze poisoning is a life-threatening emergency that requires immediate veterinary care within three hours to prevent fatal kidney failure. Even a tiny amount is toxic, so seek help immediately before symptoms appear.
What is antifreeze poisoning and why is it dangerous for cats?
Antifreeze typically contains ethylene glycol, a chemical that is extremely toxic to cats. Because it has a sweet taste, cats may be drawn to drinking puddles found in garages or driveways. Once ingested, the liver breaks it down into toxic metabolites that cause rapid, irreversible kidney failure and damage to the central nervous system.
Is antifreeze poisoning in cats a veterinary emergency?
- Antifreeze ingestion is a critical, life-threatening emergency with a high urgency level.
- Even a very small amount—less than a teaspoon—can be fatal to a cat.
- Time is the most important factor; treatment is most successful if started within 3 hours of ingestion.
- Do not wait for symptoms to appear, as internal damage occurs long before clinical signs are visible.
How does a photo of the antifreeze container help with veterinary triage?
- If you can safely do so, take a photo of the product label or the container of the antifreeze.
- This allows the veterinary team to quickly identify the concentration of ethylene glycol and check for other hazardous additives.
- Having this information ready allows the clinic to prepare the specific antidote and treatment plan before you even arrive.
Clinical Context (Merck Veterinary Manual)
Ethylene glycol (EG) intoxication is most common in temperate and cold climates. The minimum lethal dose of undiluted EG is 1.4 mL/kg body weight in cats. EG is rapidly absorbed from the gastrointestinal tract, with peak blood concentrations occurring as early as 3 hours post-ingestion in cats. Treatment involves preventing EG metabolism by decreasing alcohol dehydrogenase activity via direct inactivation or competitive inhibition. Fomepizole (4-MP) effectively inactivates alcohol dehydrogenase in dogs, but is ineffective in cats at the canine dosage. If 4-MP is unavailable, an ethanol regimen (5.5 mL of 200 proof ethanol/kg body weight, IV, every 4 hours for five treatments and then every 6 hours for four additional treatments) is recommended. Once absorption has occurred, fluid therapy is indicated to correct dehydration and increase urine production.
Chapter: Toxicology, Emergency
Source: The Merck Veterinary Manual, 11th Edition (Page 3048)