Antifreeze is extremely toxic to dogs. Ingestion of small amounts, like a tablespoon, can lead to severe kidney damage and death. If you think your dog has ingested antifreeze, take them to see a vet immediately.   

The toxin in antifreeze is called ethylene glycol. It is most often used in radiator fluid, but may also be present in some windshield de-icing products, motor oil, brake fluid, paints or solvents. Unfortunately, it has a sweet taste, so many dogs will be happy to drink it if they find it. Initially, it causes symptoms similar to being drunk (alcohol poisoning). If the dog recovers from these initial symptoms, they often develop signs of severe kidney disease 2-3 days later. Immediate intensive care is needed to prevent this from happening or support recovery if possible.

What is antifreeze toxicity in dogs? 

The toxin in antifreeze is called ethylene glycol. The lethal dose of ethylene glycol can be as low as 4.4 ml/kg. The product is quickly absorbed from the stomach and spreads throughout the body. The intoxication develops in three stages:

• In the first 30 minutes to 12 hours, the symptoms are mostly related to gut irritation and brain disruption. Severe cases may develop seizures.

• At 12-36 hours, the visible signs usually improve. However, the body’s attempt to get rid of the toxin actually causes more damage. Dehydration develops or worsens, and we may start to see changes to the heart rhythm and breathing.

• After 36-72 hours, symptoms of kidney failure develop, as well as worsening of the previous symptoms. Urine production slows down or stops. Severe lethargy may turn into coma, and some animals pass away even with intensive treatment.

Symptoms of antifreeze toxicity in dogs

First stage (30 min-12 hours):

• Drooling

• Vomiting

• Confusion or sedation

• Wobbly movement (ataxia)

• Excessive drinking

• Excessive peeing

• Seizures

Second stage (12-36 hours):

• Dry, sticky gums

• Loss of skin elasticity

• Eyes lose their shine and may appear sunken

• The heart beats faster

• Breathing may become faster and shallower

Third stage (36-72 hours):

• Complete lack of appetite

• Very low energy or sedation

• Drooling

• Bad breath that smells of ammonia

• Vomiting worsens again

• Mouth sores may develop

• Peeing reduces or stops completely

• The kidney area (below the loin) becomes painful

• Fast heart rate and breathing

• Dehydration

• Seizures

• Coma and death

Dogs at a higher risk for antifreeze toxicity

• Sadly, antifreeze poisoning can affect any dog

• It is more common in young dogs, probably due to them exploring their surroundings more

• Dogs that already have kidney problems are likely to be more severely affected

Diagnosis of antifreeze toxicity in dogs

• Blood tests are available to detect ethylene glycol, but these only work during the first 24 hours after ingestion.

• General blood and urine tests may provide some clues.

• Later in the disease process, further changes appear that can point to the diagnosis, such as the sudden formation of large amounts of calcium oxalate crystals in the urine. These changes indicate a high severity of toxicity.

• If there is any suspicion of antifreeze poisoning, it’s usually advisable to start treatment immediately and not wait for confirmation. This is because of how severe this condition is and how quickly it progresses.

Veterinary treatment of antifreeze toxicity in dogs

• The first and most important step in treating intoxication is stopping the poison from entering the blood and organs. If antifreeze ingestion is suspected, the stomach should be emptied as quickly as possible, ideally within 30 minutes. Your vet will do this with an injection or by pumping the stomach under anaesthesia. 

• Most cases will need to be hospitalised for close monitoring and treatment of the symptoms. Hydration is carefully maintained to protect kidney function.

• An antidote exists for antifreeze poisoning (fomepizole), but it may be difficult to access. Ethanol (drinking alcohol) can be used as an antidote if given as a medication, but it carries a high risk of serious side effects. 

• Intensive hospital care is usually needed for 1-3 days, more if kidney damage develops. 

Home treatment of antifreeze toxicity in dogs

Always contact a vet for advice immediately if you think your pet has ingested antifreeze. Immediate emergency care is essential. 

Prevention of antifreeze toxicity in dogs

• Antifreeze and any other products containing ethylene glycol should be carefully stored in secure, locked cabinets.

• Radiator fluid leaks should be immediately and thoroughly cleaned up.

• Dogs should not be allowed to roam around garages or vehicles that are not properly maintained.

Living with antifreeze toxicity in dogs

If absorption of the poison can be prevented and supportive care is provided, dogs may not suffer any ill effects. Unfortunately, if kidney damage develops, dogs may be left with long-term complications. This will vary from case to case.   

When to worry about antifreeze toxicity in dogs

Always speak to a vet immediately if you suspect your dog has ingested antifreeze, so the risk can be assessed and treatment advice given. 

If your dog develops any of the following symptoms, see a vet as soon as possible:

• Severe vomiting or drooling

• Confusion or wobbliness

• Weakness or collapse

• Trouble breathing

• Seizures

• Excessive drinking and urination