Are Pyrethrins & Pyrethroids toxic to cats?

These chemicals are derived from Chrysanthemum flowers or synthetic versions that cats cannot metabolize efficiently, leading to neurotoxicity. Exposure often occurs through inappropriate application of dog-specific flea medications or grooming of treated dogs.

There is no antidote. Controlling tremors and seizures comes first: in the US, the muscle relaxant methocarbamol is generally the first choice, and vets add other anti-seizure medicines or anesthesia when needed. Once the cat is stable, it gets a thorough bath with liquid dish detergent in lukewarm water. Vets also manage body temperature, because constant tremors can overheat a cat but a cold cat gets worse. They give IV fluids to keep it hydrated and protect the kidneys from muscle breakdown, check blood sugar and kidney function, and give nutritional support to cats too sick or sedated to eat.

The outlook is good when treatment is prompt and aggressive, and most cats recover fully without lasting effects. It is poorer if seizures are hard to control, or if the cat develops clotting problems or kidney failure from seizures or overheating. Cats can die from this poisoning, especially when seizures can't be controlled.

• Pyrethrins (pyrethrum) are natural insecticides made from chrysanthemum flowers. Pyrethroids, such as permethrin, are synthetic versions.
• Dog spot-on flea and tick treatments. Many contain concentrated permethrin and are labeled for dogs only. Putting one on a cat, by mistake or to save money with a 'small dog' dose or part of a dog tube, is the most common way cats are poisoned.
• A freshly treated dog. Cats are poisoned by grooming, sleeping on or rubbing against a recently treated dog, or by licking the product off it.
• Dog flea shampoos, flea collars, sprays and powders.
• Household and yard insecticides, such as sprays, foggers, liquids and granules, including walking through a treated area before it dries.
• A dog licking its own spot-on while it is still wet, licking a treated cat, or chewing and swallowing part of a flea collar.

• Never use a dog flea or tick product on a cat, not even a 'small dog' dose or part of a dog tube. Use only products labeled for cats.
• If you use a permethrin product on your dog, keep your dog and cat apart until it is completely dry. VCA advises 12 to 24 hours. A T-shirt on the dog can help prevent contact until then.
• Use the dose for your pet's weight range, and don't combine flea products unless your vet tells you to.
• Keep pets off sprayed or treated areas until they are dry.
• Store insecticides out of reach in their original containers, and never use an insecticide that isn't made for animals on a pet.