Toxic to dogs · Insecticides

Are Pyrethrins & Pyrethroids toxic to dogs?

Low severity No safe amount — No amount is considered safe.

Pyrethrins & Pyrethroids are mildly toxic to dogs. Severe cases are rare, but they can cause discomfort and are best kept out of reach. No amount is considered safe.

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Why are pyrethrins and pyrethroids toxic to dogs and cats?

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What to do right now

  1. Call your vet or an animal poison line. In the US: Pet Poison Helpline (855) 764-7661 or ASPCA Animal Poison Control (888) 426-4435. For a reaction to a flea or tick product, you can also call the manufacturer's emergency number on the package.
  2. Keep the package. It shows the active ingredient, which guides treatment.
  3. Don't make your dog vomit unless a vet tells you to, and don't give oil or fatty foods: fats help the gut absorb these insecticides.
  4. If your dog licked a wet spot-on and is drooling, offer a tasty treat or water (a little broth helps) to rinse out the bitter taste, and stop it licking until the product dries.
  5. If the product is on the skin, gently bathe your dog with liquid dish soap and cool water, as Merck advises. Don't scrub hard and don't use a flea shampoo.
  6. For a 'pins and needles' reaction where a spot-on was applied, gently brush your dog or hold a towel-wrapped cool compress on the spot for up to 10 minutes at a time. In severe cases, a poison line may advise washing the product off with liquid dish soap.
  7. Keep the treated dog away from cats until the product is completely dry.

Go to an emergency vet if

  • Your dog has tremors or a seizure, collapses or has trouble breathing.
  • Your dog ate a large amount or a concentrated product, or a product that contains bifenthrin.
  • Your dog swallowed pieces of a flea collar. Pieces can block the gut, and deltamethrin collars can cause wobbliness, hind-leg weakness, tremors or overheating.
  • Your dog's signs seem to improve and then come back.

Symptoms to watch for

  • profuse drooling
  • vomiting
  • tremoring
  • hyperexcitability
  • agitation
  • seizures
  • weakness
  • difficulty breathing
  • paresthesia
  • tingling sensation
  • scratching

How much is dangerous

No toxic dose for dogs has been published. Used as labeled, these products have a wide margin of safety in dogs, and misuse or licking usually causes mild signs such as stomach upset, drooling or skin tingling. The risk depends on the chemical, its concentration and whether it was swallowed or got on the skin. Severe signs are more likely if a dog is unusually sensitive, is exposed to bifenthrin, or eats a large or concentrated amount. Merck's general advice is that swallowing a dilute product usually needs no treatment.

When signs appear

After a dog swallows a product, signs can start within the first hour. A 'pins and needles' reaction to a spot-on can start within 15 minutes to several hours after it is applied.

Why it's dangerous

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.

Toxic compound: Permethrin

How vets treat it

There is no antidote. Vets wash off product left on the skin with liquid dish soap or a mild detergent. If a dog swallowed a product, they may give activated charcoal and sometimes a laxative, and making the dog vomit may not be appropriate. They control tremors and seizures with medicines such as diazepam or the muscle relaxant methocarbamol, may give atropine for heavy drooling, and give IV fluids while they monitor body temperature, blood sugar and kidney function. Severe cases need hospital care because signs can come back after seeming to resolve.

Outlook

The outlook is usually good with prompt treatment. Severe cases may need 48 to 72 hours in hospital. It can be poor if a dog develops seizures that can't be controlled, clotting problems, or kidney problems from seizures or overheating.

Where pets are exposed

  • 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.

Prevention

  • 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.

Good to know

Cats are very sensitive and cannot metabolize these drugs as well as dogs; dog flea and tick medications should never be applied to cats.

Common questions

Can I use dog flea treatment on my cat if I only use a little?

No. Many dog spot-ons contain concentrated permethrin, and even a small amount can make a cat seriously ill or kill it. Only use products labeled for cats, at the right dose for your cat's weight.

My cat groomed or slept on my dog after I applied flea drops. Is that dangerous?

It can be, if the dog's product contains permethrin or another concentrated pyrethroid. Cats are poisoned by grooming, sleeping on or rubbing against recently treated dogs. Call your vet or a poison line right away, and watch for twitching, tremors or wobbliness.

How long after exposure do permethrin poisoning symptoms show in cats?

Signs can start within minutes to hours, but they are sometimes delayed up to 72 hours. Once they start, they usually last 2 to 3 days, so a cat that seems fine at first still needs a vet's advice.

How long should I keep my cat away from my dog after flea treatment?

At least until the dog's product is completely dry. For permethrin products, VCA advises keeping them apart for 12 to 24 hours. A T-shirt on the dog can help prevent contact until then.

Should I bathe my cat after putting dog flea treatment on it?

Never bathe a cat that is twitching, trembling or having a seizure, because bathing can trigger seizures. Take it straight to a vet. For a cat with no signs, sources differ: Pet Poison Helpline says you can wash it with liquid dish soap if you notice within a few minutes, then call your vet, while VCA describes the bath as something the vet does once the cat is stable. If you do wash, use lukewarm water and keep your cat warm afterwards.

Why is my dog twitching, scratching or rolling around after a flea treatment?

Pyrethroid spot-ons can cause a 'pins and needles' feeling (paresthesia) where they were applied. It can start within 15 minutes to several hours, is usually not serious and often passes on its own. Gently brushing your dog or a towel-wrapped cool compress can help. Call your vet or a poison line if it is severe, or if your dog has vomiting, tremors or seizures.

Sources

This page is informational and is not veterinary advice. If your pet has been exposed to something risky, contact your vet or an animal poison control line right away.

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