Whenever I publish a post on poisoning, there always seems to be an extra bit on the end for all the odd stuff cats are additionally affected by. Why is this?
Cats are “obligate carnivores” i.e. they get all their nutritional and energy requirements from eating other animals; it’s why most vets would advise against trying to feed a vegan diet for cats. They obtain nutrients such as taurine, arachadonic acid, vitamins A and B12 from meat; they can’t get enough from plant sources.
Though they are mammals and share common enzymatic pathways with other mammals, certain pathways are heavily downregulated due to their specialised diet. For instance, livers of mammals produce an enzyme called glucuronyl transferase. This enzyme attaches another molecule to large heavy drug molecules- this makes them water soluble, and enables the liver to process them. Cats produce very little glucuronyl transferase because they have evolved not to require this to cope with their diet in the wild.
So if a cat has a paracetamol tablet (which is metabolised in the liver by glucuronyl transferase), it means they cannot process it. The levels of paracetamol stay high, producing a paracetamol overdosage extremely easily, much more so than in other species.
In addition cats tend to be very inquisitive, and have a sense of taste that leads them to ingesting compounds other species will avoid. With a generally lower body mass they are more likely to eat enough to end up being poisoned – for instance antifreeze appears to be very attractive to cats.
Sometimes we simply don’t know the mechanism of action. Lillies are extremely toxic for cats; simply groomimg after brushing by a lily plant can cause a fatal problem. In this case it appears lillies (and certain other ornamental plants) contain a toxin that attack the renal tubules- part of the filtration mechanism within the kidney.
Never give your cat any medicines or herbal supplements that haven’t been prescribed by a vet, take care with plants and prevent access to kitchen and garden chemicals. Oh, and make sure they have a high meat content diet!