Alison Richards BVSc MRCVS looks at the treatments that can do cats harm

Like any animal species, cats should only receive feline specific medications, following the advice of your veterinary surgeon.  Generally speaking, medications for other species (humans included), may not only be ineffective but could also be hugely dangerous to cats.  Cats lack certain proteins within the liver that other species use to break chemicals down so are intolerant to many medications.  As a general rule, only ever give medication to your cat following consultation with your vet.

Paracetamol – a dangerous drug for cats

Paracetamol is a painkiller that we often have in cupboards at home, but most people have no idea how toxic it can be.  Just one tablet can kill a cat.   Paracetamol also appears in liquid pain relief medication often used for children.  Most commonly, poisonings happen as a consequence of well-meaning owners trying to treat their cat, although, occasionally, a curious cat may nibble a tablet.  Therefore, all medications MUST be stored safely out of reach.

When paracetamol is digested in a cat, a toxin is produced which interferes with the red blood cells which carry oxygen around the body.  Illness happens very rapidly.  Common symptoms include depression, a darkening of the gums to a deep red, swelling of the paws and face and breathing difficulties.  This can progress to vomiting, your cat’s skin may turn yellow, and any urine they pass may turn dark brown.

If you suspect your cat has consumed paracetamol, or you notice any symptoms, it is vital you get them to the vet urgently.  Death is very likely unless they are treated rapidly, and many cats won’t survive if treatment is given more than an hour after consumption.  At the vets explain your cat has consumed paracetamol and how much your cat has had.

There is a specific treatment called acetylcysteine available from human hospitals.  Alongside this, your vet may try and make your cat sick and give a product called activated charcoal which can prevent some of the paracetamol being absorbed.

If you are concerned your cat is in any sort of pain, always consult your vet and only ever give pain relief medications specifically for cats under their guidance.

Dog flea treatments are just for dogs!

Permethrin poisoning is one of the most common poisonings of cats.  Permethrin is an insecticide that is found in high concentrations in some spot-on-flea treatments designed for dogs and can cause serious illness in cats.  Often people assume cats will tolerate a smaller dose of a dog medication, but this is not the case.  Poisoning may also occur when a dog has been treated with a permethrin-containing product and a cat rubs up against them, or the area where they’ve been sitting.

Symptoms involve the nervous system: twitching, trembling, shaking, walking as if drunk, and oversensitivity to noises or movement commonly seen.  In severe cases cats may seizure.  If you suspect your cat has been in contact with permethrin, seek urgent veterinary treatment.  Your vet will first try and remove the product by bathing your cat in diluted washing up liquid.  They may have to control symptoms such as seizures with medication.  Most cats treated rapidly, before significant seizures start, will make a good recovery.

Prevention is key.  Only use flea treatments specifically designed for cats, never use a dog treatment on a cat.  Take care if you order your flea treatment on the internet, as it can be more difficult to assess whether the product is specifically intended for cats.  Once you have your product, ensure you follow the manufacturer’s instructions.   A small number of cat flea treatments (mostly flea powders) contain a very low concentration of permethrin that is safe if used correctly.  Talk to your vet about the most appropriate flea treatment to use.  If you have a dog and a cat, avoid the use of dog flea products containing permethrin – your vet can advise on the best treatment. If it really is unavoidable, then it is recommended that you keep your dog and cat separated for at least 72 hours after treatment.  If in doubt, get in touch with your vet.  


This article first appeared in the Autumn 2019 issue of The Cat magazine, which is distributed by Cats Protection.  My appreciation and gratitude to Francesca Watson, editor of The Cat magazine for giving me permission to use it on The Daily Mews website.

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