Antifreeze Poisoning

Antifreeze, or ethylene glycol, is a common toxin our pets are exposed to. Pet owners will often not realize their car is leaking in the garage or not think twice about the unidentified puddle their pet drank from. Because antifreeze has a sweet taste to it, pets will readily drink large quantities. It only takes a small amount for severe toxicity to develop.

Ethylene glycol causes rapid kidney failure. It can take as a little as a few teaspoons of antifreeze for kidney failure to develop. The antifreeze toxicity takes effect quickly, with symptoms developing in 30 minutes.

Early signs are similar to alcohol intoxication, including nausea, vomiting, increased thirst and urination, and loss of coordination. At this stage, the ethylene glycol will begin to form crystals in the kidneys and crystals can be seen in the urine. Depending on the amount ingested, seizures and coma can also be seen. In the later stages of toxicity (12-24hrs after exposure), an increase in heart rate and breathing rate occur. Unfortunately, the final stage occurs 24-72 hours after exposure, and kidney failure sets in.  Pets are often severely lethargic, are urinating small amounts, and continue vomiting with possible seizures, coma, and death.

Due to its quick absorption, immediate action is necessary. There is an antidote available, but it must be given in a timely manner. Cats must receive treatment within 3 hours of ingestion, and dogs must receive treatment within 8 hours of ingestion to prevent kidney injury.

Once treatment has started, your veterinarian will likely want to hospitalize your pet for further monitoring and treatment. Apart from supportive care, your veterinarian will want to monitor your pets kidney function, urine output, and monitor for crystal formation in the urine.

If treated promptly and aggressively, pets recover well from antifreeze poisoning. Timing plays a major factor in treatment and recovery. If you suspect your pet has ingested antifreeze, contact Pet Poison Helpline® or your local veterinarian immediately.


Written by:

Gabi Oliveira, PPH DVM student extern, University of Illinois College of Veterinary Class of 2023 &

Lizzy Olmsted, CVT, Veterinary Information Specialist