Antifreeze Toxicity

Ethylene glycol, a sweet-tasting, odorless liquid, is the active ingredient in most automotive antifreeze products. Ethylene glycol can also be found, in lower, less harmful, concentrations, in some windshield de-icing agents, hydraulic brake fluid, motor oils, solvents, paints, film processing solutions, wood stains, inks, and printer cartridges.

How do dogs and cats get ethylene glycol poisoning?

Pets may be attracted to ethylene glycol by its sweet taste. Many animals voluntarily drink ethylene glycol if antifreeze is spilled or leaks onto garage floors or driveways. Ethylene glycol has a very narrow margin of safety, which means a tiny amount can result in severe poisoning. 

What are the signs of ethylene glycol poisoning?

Ethylene glycol poisoning is divided into three stages.

Stage 1 (within 30 minutes of ingestion): The signs include lethargy, vomiting, incoordination, excessive urination, excessive thirst, hypothermia (low body temperature), seizures, and coma.

Stage 2 (12 to 24 hours after ingestion): Some of the signs seem to dramatically improve. However, during this stage, dogs become dehydrated and develop an elevated breathing and heart rate.

Stage 3 (36 to 72 hours after ingestion): At this stage, signs of severe kidney dysfunction may occur, characterized by swollen, painful kidneys and the production of minimal to no urine. Progressive depression, lethargy, lack of appetite, vomiting, seizures, coma, and death may be seen.

It is critical that you contact your veterinarian or Pet Poison Helpline, a 24/7 animal poison control center, at (855) 764-7661, if you know or even suspect that your pet has consumed ethylene glycol, or if they exhibit any of the early symptoms. Do not wait; time is of the essence and immediate treatment is essential. Dogs must be treated within 8–12 hours of ingesting antifreeze, as the antidote only has a short timeframe to work. Left untreated, the animal may die.

How will my vet diagnose antifreeze poisoning?

Some veterinary hospitals have an in-house test kit that can detect the presence of ethylene glycol in the bloodstream. However, these types of tests may not be as accurate, and false positives can be seen (from exposures to other alcohols, such as propylene glycol, glycerol, mannitol, isopropyl alcohol, sorbitol, etc.). This test should be performed within 6 hours of exposure to ensure accuracy, or it could result in a false negative. Since peak levels of ethylene glycol are detected in the first 1–6 hours after ingestion of the toxin, it is important that this test be used early during suspected poisoning. By as early as 24 hours after ingestion, insufficient ethylene glycol remains to allow detection on this blood test, but the damage to your pet’s body has already occurred.

Are there other tests that can indicate ethylene glycol poisoning?

Ethylene glycol is converted by the liver into toxic byproducts that damage the kidneys. This damage can be identified in a serum biochemistry profile. However, these tests are not specific for ethylene glycol poisoning, and by the time these blood tests show evidence of kidney failure, the prognosis is grave to poor, as it is too late to treat with the antidote.

A urinalysis may also confirm ethylene glycol poisoning and underlying kidney damage. And lastly, a special black-light lamp (Wood’s lamp) can sometimes be used to examine the urine, muzzle, and paws of the patient to look for the presence of the warning dye that is added to automotive antifreeze.

How is antifreeze poisoning treated?

Because antifreeze poisoning can easily be fatal, immediate first aid needs to be administered extremely carefully. Only induce vomiting if you are positive your dog has ingested antifreeze. We recommend calling your veterinarian before inducing vomiting, since this can be dangerous in some instances of poisoning as the esophagus can be seriously damaged by some substances. If your dog has already vomited, do not try to induce more vomiting.

Vomiting should also not be induced if your dog is having problems breathing, is in serious shock or distress, or is unconscious. Also, whether he vomits or not, your dog must be immediately rushed to your vet, who can safely administer antidotes.

Antidotes may include activated charcoal, which will stop further absorption of the ethylene glycol. 4-methylpyrazole or ethanol can also be used to effectively treat antifreeze poisoning if given quickly enough after your dog has ingested it. There is still a possibility of kidney failure, so your dog may need to be in intensive care.

Dogs who have consumed antifreeze in very small amounts may survive, but will develop kidney failure within days of ingestion. Kidney damage kills many dogs who have been poisoned by antifreeze.

How can I prevent antifreeze poisoning?

While antifreeze can do devastating damage to your dog’s system, poisoning is preventable. Here are some steps to take today:

• Propylene glycol is safe, according to the U.S. Food and Drug Administration. Look for antifreeze with this ingredient, which can keep your pet safer from ingesting ethylene glycol.

• Do not allow your dog to wander where they may have easy access to antifreeze, such as in driveways, garages, streets, etc.

• Inspect your car’s radiator on a regular basis, and have leaks repaired immediately.

• Close antifreeze containers tightly, and keep them out of reach of your dog’s curious nose.

• Ensure any antifreeze spills are immediately and thoroughly cleaned.

• Dispose of used antifreeze containers properly.

If you suspect antifreeze poisoning in your pet, please seek immediate medical attention. Contact your veterinarian or local Urgent Care or Emergency Vet Clinic.