ethylene glycol, EG
Toxicity to pets
Antifreeze, which often contains ethylene glycol (EG), can be extremely dangerous to dogs and cats. Sources of ethylene glycol include automotive antifreeze (radiator coolant, which typically contains 95% ethylene glycol), windshield deicing agents, motor oils, hydraulic brake fluid, developing solutions for photography, paints, solvents, etc. As little as a tablespoon can result in severe acute kidney failure in dogs, while as little as 1 teaspoon can be fatal to cats. When dogs or cats are exposed to a toxic dose of ethylene glycol, immediate treatment is necessary. Some “pet-safe” antifreeze products contain propylene glycol, which is much safer than ethylene glycol if ingested.
Three stages of poisoning can be seen with ethylene glycol:
Stage 1: This occurs within 30 minutes to 12 hours, and looks similar to alcohol poisoning. Signs of incoordination, drooling, vomiting, seizures, and excessive thirst and urination may be seen.
Stage 2: This occurs within 12-24 hours post-exposure, and clinical signs seen to “resolve” when in fact more severe internal injury is still occurring.
Stage 3: In cats, this stage occurs 12-24 hours after ethylene glycol exposure. In dogs, this stage occurs 36-72 hours post-ingestion. During this stage, severe acute kidney failure is occurring. Signs of inappetance, lethargy, drooling, vomiting, seizures, and coma may be seen.
Treatment for ethylene glycol poisoning includes the antidote fomepizole (also known as 4-MP) or ethanol. Fomepizole is expensive but life-saving when administered to dogs within the first 8-12 hours of ingestion. In cats, the antidote must be administered within 3 hours of ingestion to be effective; after this time period, ethylene glycol poisoning is almost 100% fatal without hemodialysis. Aggressive therapy is necessary to survive.
The content of this page is not veterinary advice. A number of factors (amount of substance ingested, size of the animal, allergies, etc.) determine what is toxic to a particular pet. If you think your pet has eaten something potentially toxic, call Pet Poison Helpline or seek immediate veterinary treatment.