Ethylene Glycol (Antifreeze) Toxicosis in Dogs


Overview of Ethylene Glycol (Antifreeze) Toxicity in Dogs

Ethylene glycol toxicosis is a type of poisoning that occurs in dogs after ingestion of antifreeze or other fluids containing the ingredient ethylene glycol. Ethylene glycol itself is not toxic, but it is metabolized in the animal’s body to several extremely toxic chemicals that are responsible for its potentially lethal effects.

Potential sources of ethylene glycol in the environment include antifreeze (the most common source of ethylene glycol poisoning), air-conditioning coolants, brake fluid, heat exchange fluids from solar collectors, and fluids used in color film processing.

Ethylene glycol poisoning symptoms in the nervous system and severe kidney failure with almost complete cessation of urine output. Ethylene glycol poisoning can be fatal if not treated soon after ingestion (within 4 to 8 hours).

Dogs that roam outside unsupervised are more likely to encounter ethylene glycol in antifreeze which has been disposed of improperly. Ethylene glycol has a sweet taste and dogs will consume it readily. Unfortunately, many owners do not realize that their pet has consumed ethylene glycol and don’t become aware of the problem until the pet shows non-specific symptoms of kidney failure like loss of appetite, lethargy and vomiting two to three days later. Treatment is often futile after severe kidney failure has developed.

The minimum lethal dose for dogs averages five milliliters per kilogram of body weight. Thus a little more than three tablespoons (or 45 milliliters) could be lethal for a 22 pound (10 kg) dog.

Definitive treatment should be started as soon as possible after consumption of ethylene glycol (within a few hours). If treated promptly and appropriately, pets that have consumed ethylene glycol will not develop kidney failure and have a good chance of survival.

What to Watch For

Signs of Antifreeze toxicosis in dogs may include: 

  • Nausea
  • Vomiting
  • Increased thirst
  • Lethargy
  • Incoordination progressing to coma.

    Dogs may act as if they are intoxicated. These signs develop within 30 minutes to 12 hours after ingestion of ethylene glycol depending on the amount ingested.


    Diagnosis of Antifreeze Toxicity in Dogs

    Diagnostic test are needed to recognize ethylene glycol toxicosis, including:

  • Complete medical history and physical examination
  • Ethylene glycol test should be performed as soon after ingestion as possible
  • Urinalysis to evaluate for characteristic calcium oxalate crystals (one of the metabolic end-products of ethylene glycol breakdown), casts, and other evidence of kidney damage
  • Blood gas analysis to evaluate for the presence of severe acidosis
  • Serum biochemistry tests to evaluate for electrolyte disturbances (including low blood calcium) and abnormally high kidney function tests (blood urea nitrogen, serum creatinine, serum phosphorus)
  • Abdominal ultrasound examination to evaluate kidney size and appearance. Deposits of calcium oxalate crystals in the kidney result in a very bright (white on the ultrasound monitor) appearance within hours
  • Kidney biopsy to confirm ethylene glycol poisoning if kidney failure is present
  • Treatment of Antifreeze Toxicity in Dogs

    Treatment for ethylene glycol toxicosis in dogs includes one or more of the following:

  • Induction of vomiting by oral administration of hydrogen peroxide if possible before transport of the pet to the veterinary hospital
  • Hospitalization of the pet usually is necessary
  • Induction of vomiting (if not successful before arrival) and gastric lavage (pumping of the stomach) to remove the poison before it can be broken down to its toxic end-products
  • Administration of activated charcoal to bind ethylene glycol within the digestive tract
  • Intravenous fluid administration to correct dehydration
  • Treatment with sodium bicarbonate if acidosis is severe
  • Specific drugs such as 20 percent ethyl alcohol or 4-methylpyrazole (Antizol®) that inhibit the breakdown of ethylene glycol to its toxic end-products if the pet is seen within several hours after ingestion of ethylene glycol
  • Drugs to treat kidney failure and encourage urine production such as the diuretic furosemide and blood vessel-dilating drug dopamine. Unfortunately, these drugs are not often effective once severe kidney failure has developed and more than 80 percent of pets with kidney shutdown due to ethylene glycol poisoning die despite diligent medical treatment
  • Peritoneal dialysis or hemodialysis is necessary if severe kidney failure and shutdown of urine production are present. These procedures require referral to a veterinary specialist.
  • Home Care

    Remove your dog from the source of ethylene glycol immediately. Call your veterinarian immediately if you suspect your dog to have consumed ethylene glycol. Your veterinarian may recommend you induce vomiting in your pet by oral administration of hydrogen peroxide. Transport your pet to your veterinarian immediately.


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