The dangers of antifreeze

As the days get cooler, the use of antifreeze becomes more common and the risk of intoxication to our pets also increases. Although essential to keep our cars on the road, antifreeze is toxic to cats and dogs. It can kill them. Most antifreezes contain ethylene glycol. This toxin is metabolised in the body to produce multiple different toxic by-products, including glycolic acid and oxalate, both of which are highly toxic to the kidneys. Cats are even more susceptible than dogs, and a much smaller dose may prove fatal. The symptoms also progress faster, and are more subtle and harder to recognise.

Which solutions should I be aware of?

Antifreeze solution can be found in screen washes, brake fluid, hydraulic fluid, some inks and as coolants in a wide range of machinery. All of these products should be stored high up out of the reach of animals but be aware that many cats like to climb. All lids should, therefore, be put on securely. If any solution gets spilt, it should be cleared up as soon as possible.

What are the symptoms following intoxication?

Common symptoms following intoxication include:

Vomiting, depression, weakness, urinating a lot, abnormal walking pattern and coldness. This is similar to drunkenness in humans (and in fact, ethylene glycol is processed the same way in the body as alcohol).

The animal will then seem to recover, and seem normal. However, the glycolic acid builds up in the kidneys, and 1-3 days later the kidneys will start to fail. The symptoms at this stage include increased thirst, altered urination (increased urine production in the mildest cases, reduced or absent urination in more severe poisonings), abnormal behaviour, a metallic smell on the breath, seizures, collapse and eventually death.

The symptoms vary depending on the length of time since the antifreeze was consumed. The vet may be able to tell you more specifically when the intoxication occurred, as the toxins normally affect the central nervous system function first and then the urinary system.

How long does it take for the symptoms to show?

The initial symptoms normally occur between 30 minutes and 12 hours. If you notice your pet has drunk some, seek medical attention urgently. Symptoms can vary in onset time and severity. Symptoms change between 12 and 72 hours, so do not think because the behaviour continues to change, your pet has got better. This may be the toxins progressing in their damage.

What should I do if I think my pet has swallowed antifreeze?

Vet attention should be sought URGENTLY. Although alcohol can be used as an antidote do NOT try to administer this yourself. Alcoholic poisoning is also likely to be fatal in dogs and cats, and they need full monitoring and intensive care, not a bottle of brandy at home!

Can it be treated?

Treatment varies depending on how soon you bring the animal into the practice.

During the visit to the vets, we will assess the level of toxicity. We can administer a competitive inhibitor of alcohol dehydrogenase, Fomepizole, to prevent the conversion of ethylene glycol into its toxic by-products. Unfortunately, this is expensive and hard to get hold of, so it depends if we have any in the practice. Intoxication causes acidosis which can be treated with sodium bicarbonate. We will monitor renal function carefully throughout their stay. Additionally, we can provide fluids intravenously, which help support the pet and ensures administered drugs reach target sites quicker. Ethanol cannot be given if renal failure has occurred (another reason not to try this yourself!).

If your pet has entered renal failure, the prognosis is poor as treatment options are limited.

What is the prognosis?

The sooner the treatment occurs, the better the prognosis. Most survive if they present early, but if the pet has entered renal failure, the prognosis is very poor.


Think your pet might have been exposed? Call us IMMEDIATELY.