Clinical Signs of Antifreeze Toxicity in Dogs and Cats

Veterinarian with Dog in Veterinary Medicine Animal Pet Clinic Hospital
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Acute cases of antifreeze toxicity (when an animal consumes antifreeze) often present as if the animal is intoxicated with alcohol. The kidneys are the target organ; antifreeze destroys the kidney tissue.

This is an emergency situation and life-threatening within hours. If you suspect ethylene glycol ingestion by your pet, please see your veterinarian immediately, as the success of treatment depends on how quickly your pet can get medical care.

What Is Antifreeze Used For?

Antifreeze is a syrupy liquid that is usually brightly colored; neon green or neon pink. It may be found leaking under cars in the heat of summer or after engine maintenance. Spills of this liquid are also common in winter months as car owners perform seasonal engine maintenance.

Antifreeze is used in the plumbing systems of cabins and other vacation homes in extreme climates to prevent broken pipes in winter. Antifreeze may also be used to weigh down portable basketball hoops.

This chemical is an ingredient of de-icers, hydraulic brake fluids, and photograph-developing chemicals. Antifreeze is odorless and has a sweet taste, which can be attractive to curious and thirsty animals and children.

Early Stage of Antifreeze Toxicity

Acute cases of antifreeze toxicity (within 12 hours of ingestion) often present as if the animal was intoxicated with alcohol, exhibiting an unsteady gait.

Signs may include: 

  • Stumbling, unsteady gait
  • Vomiting
  • Depression
  • Seizures
  • Increased urination initially (in later stages, the urinary output is decreased)
  • Increased thirst 

Antifreeze Toxic Effects on Kidneys

The kidneys are most severely affected, and even if the animal seems to improve initially with treatment, they may succumb shortly after to kidney failure (3-5 days post-ingestion). The kidneys shut down, and the animal is unable to produce urine.

This type of kidney failure usually happens 12-24 hours after ingestion in cats, and 36-72 hours post-ingestion in dogs. Again, the success of the treatment is dependent upon quick treatment. If antifreeze ingestion is known or even suspected, do not delay — contact your veterinarian immediately. This is not a "wait-and-see" situation; kidney damage will be more severe as time (hours) go by.

A Safer Antifreeze Alternative

A safer alternative to traditional antifreeze (ethylene glycol) is propylene glycol. Like ethylene glycol, propylene glycol is odorless but differs in that it is virtually tasteless and does not cause kidney damage like traditional antifreeze. Though safer than ethylene glycol, propylene glycol ingestion can still cause side effects and poisoning if ingested in large quantities so it is best to keep your pet away from all antifreeze.

The ASPCA reports that most ethylene glycol toxicities occur around a pets home and are usually due to improper storage or disposal of ethylene glycol products. Though vets and poison control organizations have tried to warn about ethylene glycol toxicities, these poisonings continue to happen each year. To help prevent these potentially deadly toxicities, the ASPCA recommends the following steps:

  • Always clean up antifreeze spills immediately
  • Never allow your pet access to an area where you are draining radiator fluid
  • Check your car regularly for leaks
  • Always store antifreeze containers in marked and sealed containers elevated in areas inaccessible to your pets
  • Consider propylene glycol products instead which have a wider margin of safety
  • Encourage one another and family members to pay attention to ethylene glycol products and never leave them out in the open even if you believe an animal can not access it in that location
If you suspect your pet is sick, call your vet immediately. For health-related questions, always consult your veterinarian, as they have examined your pet, know the pet's health history, and can make the best recommendations for your pet.