What do all these products have in common? Each of the above items (except the Hartz product) contains 45-65% permethrin, a synthetic insecticide. (The last item contains phenothrin, a similar agent.) Permethrins have a good margin of safety in dogs, but even a small amount of any of these products are TOXIC to cats.
Pyrethrins are the natural pesticides derived from chrysanthemum flowers, which are very safe and which break down quickly. They can be used in cats and young animals with little to no risk of injury. (Note: Anything is potentially toxic to an animal with a sensitivity to that agent.) Man-made pyrethoids like permethrin last a lot longer and are safe for dogs. The packages always bear warning labels saying not for use in cats, though some are more obvious than others. There are at least 18 different permethrin products available, and it doesn't matter if you get one from a veterinarian, the Internet, a pet store, or any other source - permethrins extremely toxic for cats.
Permethrin toxicity is one of the most commonly encountered poisonings in cats. While some cases occur accidentally, most are
Permethrin toxicity is one of the most commonly encountered poisonings in cats. While some cases occur accidentally, most arecaused by owners who deliberately ignored the package labels, applying it to cats in spite of the cautions. I can’t count the number of permethrin toxicities I have treated over the years, and every case was caused by operator-error. Excuses were usually “I just put on half; I only used a little,” and so forth. NOT FOR USE ON CATS means none, never, ever, not even half the tube, not even a little bit, none whatsoever.
Other cases are the result of accidental application, or rarely by cats coming in close contact (grooming, cuddling) with dogs who have had these products applied. My cats frequently snuggle up with my dogs – I won’t have a permethrin product in my house.
Signs may appear within a few hours but can take up to 72 hours to show up. Muscle tremors are most common, and seizures may occur. With aggressive (and expensive) treatment (decontamination, IV fluids and medications like methocarbamol for tremors and diazepam for seizures) the prognosis is good.
If you accidentally apply a dog product to your cat, bathe it in Dawn dish detergent immediately and contact your vet. If your cat is already symptomatic, skip the bath and go directly to an emergency service for intensive care.