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Pyrethrins & Pyrethroids

Poisonous to: Cats, Dogs

Level of toxicity: Generally mild to severe, life-threatening

Common signs to watch for:

  • Profuse drooling
  • Vomiting
  • Tremoring
  • Hyperexcitability
  • Agitation
  • Seizures
  • Weakness
  • Difficulty breathing

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Pyrethrins are a class of drugs derived from the Chrysanthemum flower/plant, while pyrethroids are synthetic derivatives. Pyrethrins and pyrethroids typically come in varying concentrations (from < 1% to up to 55% or more). Higher concentrations can be safely used on dogs; however, cats are very sensitive to these chemicals and cannot metabolize these drugs well as dogs. One of the most common ways we see cats being poisoned by pyrethrins is by inappropriate application of dog flea and tick medications placed on a cat; this should never be done without consultation with a veterinarian. Less commonly, cats may be poisoned by licking or grooming a flea and tick medication off a dog that had recent topical spot-on application.

In cats, signs of poisoning include profuse drooling, vomiting, tremoring, hyperexcitability, agitation, seizures, weakness, and difficulty breathing. Untreated, it can be fatal. These signs are rarely seen in dogs. In dogs, signs of parasthesia (a tingling sensation), scratching, drooling, etc. may be seen. Treatment includes prompt removal of the product (by bathing with a liquid dish soap like Dawn, Joy, Palmolive) to get the greasy substance off.

If you think your dog or cat are having side-effects or were exposed to pyrethrins/pyrethroids, call your veterinarian or Pet Poison Helpline immediately for life-saving treatment advice.

Poison type: Insecticides

Alternate names: pyrethroids, Chrysanthemum, flea and tick topical spot-on medications, bifenthrin, permethrin, allethrin, tetramethrin, cyfluthrin, cyhalothrin, cypermethrin, deltamethrin