Tox Talks: Why Antifreeze is Dangerous to Your Pet

As we come into the warmer months of the year (and especially coming out of quarantine), there is increased interest in pursuing travel and outdoor activities.

Many of these activities can revolve around or involve vehicles and their maintenance – especially for people who like to complete work on their cars at home.

As with all other activities, these too come with increased exposure of toxins to our pets! One of the most dangerous exposures related to these activities is that of ethylene glycol or “antifreeze.”

We asked  Brandon Sonn – a Licensed Veterinary Technician on the Petzey network who specializes in toxicology – to help us understand why antifreeze is dangerous to our pets.

From general health questions to urgent concerns, use the Petzey app to talk or video chat with a credentialed vet professional to get answers in minutes. If a trip to the vet clinic or hospital is needed, we’ll help find ones near you.

Why is antifreeze so dangerous?

When changing out your car’s coolant, it is very easy for some to leak off to the side and drip out under the car. Additionally, these bottles of coolant can develop leaks if damaged while moving them, the cap isn’t screwed all the way back on or it may have been purchased with a small leak already.

Regardless of the cause of the leak, if our pets drink the leaked antifreeze, it can have very serious life-threatening consequences. What’s scarier is that our pets only need to consume a very small amount for it to be fatal. Since antifreeze is supposed to have a slightly sweet taste, it can be appealing for our pets to want to drink it (or keep drinking if they have started). We all know that our animals are curious and will try to eat or drink most things at least once!

How much antifreeze is lethal?

An example of how little antifreeze needs to be consumed for damage to occur, an average-sized cat (13 pounds) would need to drink less than 2 teaspoons of antifreeze for a lethal dose. A large dog (75 pounds) would need to drink half a cup to be lethal as well. 

How do I know my pet drank antifreeze?

Within the first 30 minutes to 12 hours after drinking some antifreeze, the signs of toxicity your pet will show are what I refer to as their “drunk signs” such as:

  • Stumbling around
  • Being off-balance
  • No normal responses to stimuli
  • Drinking and urinating a lot
  • Nausea or vomiting
  • Overall have a generally depressed mood

These signs are caused by the ethylene glycol itself because the toxin is in the family of chemicals known as “alcohols.”

While these symptoms and this stage of intoxication may not pose a lethal threat, it is critical to have these pets be treated by a veterinarian ASAP. I have unfortunately observed too many people thinking it was funny that their pet was acting drunk and waiting to bring them into the hospital until it’s too late.

What happens after the “drunk” phase?

The later (or secondary) signs represent the true danger that our pets face when consuming antifreeze. These symptoms are caused by the metabolites of ethylene glycol as it is broken down within their bodies. For cats, this happens in only 12-24 hours! Dogs do not have much more time – only about 36-72 hours at most before the damage becomes irreversible.

More severe symptoms include:

  • Lethargy and/or comatose
  • Seizures
  • Continued vomiting (and likely anorexia)
  • Ulcerations in their mouths with lots of salivation
  • Inability to urinate

As ethylene glycol is metabolized, it forms calcium oxalate crystals that become lodged in and severely damage their kidneys. These crystals can damage multiple parts of the body, but the kidneys tend to be the primary target of injury. Unfortunately, kidneys lack the ability to regenerate after they have been damaged, so these injuries become permanent. If the damage is severe enough, they will no longer be able to produce urine which is a critical process for all living creatures to remove waste metabolites from our bodies.

Therefore, it is extremely important to bring them to a veterinary hospital as soon as possible to begin diagnosis and treatment to help save their life. 

What do I do if my pet drank antifreeze?

If uncertain about whether or not they have ingested any antifreeze, consulting symptoms with a veterinary professional can help you determine if going to the hospital immediately is the most prudent choice. From there, the hospital will have specific tests to confirm ethylene glycol exposure.

Be careful with all of those car maintenance activities at home. We need to be responsible for preventing our pets from getting into very dangerous toxins like ethylene glycol!

Got questions about pet toxins? Use Petzey to talk or video chat with a credentialed vet professional to get answers right away, all for only $20 a consultation.

This information is offered for informational and educational purposes only, and is not intended to replace traditional veterinary medical advice or create a veterinarian-client-patient relationship. You should not change your pet’s care or treatment on the basis of this information. If you think your pet requires emergency assistance, you should take your pet to the nearest emergency veterinary hospital.