Antifreeze is used commonly in car radiators and some screen washes, but it is extremely toxic to cats and dogs.
Cats like drinking from puddles, ponds and standing water which makes the outdoor cat quite prone to drinking contaminated water. In addition it is very sweet, so cats and dogs like the taste. The lethal dose for cats is only the equivalent of a 6ml teaspoon full.
The active ingredient in antifreeze (and other products) is ethylene glycol and once drunk is rapidly absorbed into the body. Within hours it causes severe kidney damage which is very difficult to treat and in one recent report involving 25 cases, 96% died.
With such a lethal product prevention is absolutely key. If you are using antifreeze or any product containing Ethylene Glycol please be very careful where you store it and if you spill any, please clear this away. If you have an ornamental garden pond, please don’t add antifreeze to it in the winter time. It may keep your fountains running in a cold snap, but could risk your cat’s health.
If you do suspect your cat has drunk antifreeze then you should call a vet straight away. If the cat is treated immediately after exposure it may be treated successfully. The first sign you see may be wobbliness or falling over (as if drunk). The back and kidney area can be very painful, there may be vomiting and your cat may be very thirsty. This is all secondary to kidney damage which ultimately leads to the tragic outcome of death. Your cat will need intensive treatment, but unfortunately the survival rate is very low if the kidneys have been damaged and cats are often put to sleep on presentation at the vets.
Antifreeze is one of the most life threatening poisonings that vets see, but there is some hope as there is a safer alternative. Propylene Glycol antifreeze is more expensive but safe for pets and other wildlife, so if you have a cat, consider using this instead.