Don’t save money by using dog flea and tick treatments on cats

In the UK there is a cost-of-living crisis due to various factors including high inflation caused mainly by Putin’s invasion of Ukraine. There are similar problems on the European continent. People want to save money wherever they can which may encourage people to save pennies when treating their cat and dog for fleas and ticks. The kind of question you might ask is: I have a nine-pound cat and a five-pound Chihuahua, is it okay to apply half of the monthly flea treatment and tick preventative on my dog and the other half on my cat? That plan won’t save money. It will cost a hell of a lot more combined with masses of emotional distress.

Don't use dog skin parasite treatments on cats or permethrin treatments on dogs if they live with cats
Don’t use dog skin parasite treatments on cats or permethrin treatments on dogs if they live with cats. Image: MikeB
Until September 7th I will give 10 cents to an animal charity for every comment. It is a way to help animal welfare without much effort at no cost. Comments help this website too, which is about animal welfare.

Yes, the answer to that question is clear and cat and dog owners should never deviate from this answer. You cannot share cat and dog flea treatments among cats and dogs as if they are the same species of animal. This is because they simply are not; particularly with regard to their reaction to the insecticides found in tick and flea treatments.

The bottom line is that you have to read the instructions on the treatment word for word, no skimping because if you screw up and administer permethrin insecticide to a cat that was designed to be administered to a dog you will severely harm your cat or worse: death. For a pet owner, there is no worse human behaviour than killing your cat carelessly.

Liver metabolism varies between cats and dogs. Cats are very sensitive to permethrin and other pyrethroids which don’t harm dogs. Therefore, canine flea and tick treatments containing these toxic chemicals must never be applied to cats.

There is an underlying point to this short post: flea and tick treatments are very toxic to cats and dogs unless the instructions are followed very carefully. These are nasty chemicals which can harm and personally I never use them. There have been some uncomfortable stories on the internet, for example:

It is ironic that in the instructions for applying spot-on insecticide treatments the manufacturers state that the person applying the treatment needs to wash their hands thoroughly after using the product. This tells us how toxic it is and yet we are putting it on our cat’s skin and leaving it there. It seems entirely wrong to me.

Because cats are very sensitive to permethrin it can cause great toxicity, the signs of which include tremors, loss of coordination, seizures, twitching, excitability, weakness, drooling, dilated pupils, loss of appetite, diarrhoea and emesis. Many cats exposed to pyrethroids die. The damage starts in 1-12 hours and lasts for 3 days.

And it doesn’t mean that you have to physically share the product between cat and dog. You can give it to your dog only and your cat can rub up against your dog and the product can be transferred from dog to cat. It is deposited on her fur, and she licks it off. If you have a cat and a dog, you cannot use pyrethroid-containing pesticides such as permethrin on your dog as the product may end up on your cat.

I would make an absolute rule against using the stuff, but veterinarians might state that you can use it provided you let the product dry before your cat and dog make contact with each other. I think that’s too risky because it is going to require careful monitoring and a lot of people are not up to it. The risks are too high.

The basic rule is to buy separate products for cats and dogs and apply them exactly as per the instructions. And my basic rule is to not use insecticide products on cats at all but to ensure that the home is flea-free and that you flea comb your cat at least once per day. Do everything in a physical way rather than chemically. I don’t trust chemicals when applied to a precious cat companion.

Annually, hundreds of cats are killed because their owners treat them with dog flea medication. The Veterinary Poisons Information Service in the UK found that 10% of cats referred to them had died after being exposed to flea treatments containing permethrin. This is a deadly chemical to cats which is in fact mildly toxic to most mammals in any case.

In the study, 286 cases of cats treated with spot on permethrin caused poisoning in 97% of them. One in 10 of them died or were euthanised. The numbers are shocking, and they should be a powerful warning to cat owners to avoid this nasty chemical. Just read the instructions and take your time before going down the route of applying spot on treatments for ectoparasites.

Here are 3 more articles on this topic. There are on this website. Please search for them using custom search.

Flea treatments can kill or cause harm: please read the instructions and use caution

Dog Flea Treatments Kill Cats

Herbal Cat Flea Remedies Are No Safer Than Conventional Treatments

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