There is an antidote to paracetamol poisoning in cats. Some people take overdoses of paracetamol. An antidote has been developed and is available at (some?) hospitals. Cats are not that infrequently poisoned, either deliberately or accidentally. A cat might chew on a paracetamol tablet if it is left lying around. Painkillers for humans should not be used on cats unless under the advice of a veterinarian (see Feline Pain Relief). Accordingly, if a cat does chew or swallow a paracetamol tablet it may prove fatal and speedy action is required to treat the cat. In humans the antidote is best given within 12 hours of ingesting the paracetamol when a complete recovery can be made (src: pharmweb.net). Up to 48 hours after overdosing a human may may still gain benefit from taking the antidote, which I understand to be called, methionine.
In the case of a cat called Smudge, living in Poole, Dorset, England (south coast) who had swallowed a paracetamol tablet the antidote worked but it was hard to find a place that dispensed the medicine. Smudge's keeper, Becka Johnson, found that her vet did not have supplies of the antidote to paracetamol poisoning in cats and neither did other vets in the area. She was referred to a local hospital (for people!) and they did have the antidote. She had to take the antidote back to her vet to administer it in the correct amount.
Smudge appears to have recovered. Smudge's nose and gums became bright blue and he was drowsy. Paracetamol damages the liver.
Antidote to Paracetamol Poisoning in Cats -- Photo by patrick h. lauke: published under a Attribution-NonCommercial-NoDerivs creative commons License -- this site is for charitable purposes in funding cat rescue.