Pyrethrin and Pyrethroid Poisoning in Cats

What are pyrethrins and pyrethroids?

Pyrethrin insecticides are naturally derived from the chrysanthemum (“mum”) flower, and pyrethroids are the synthetic (artificial) versions of this chemical. Pyrethroids are commonly found in products used around the home for insect control, including:

• Home and outdoor yard and garden insecticides (these typically come in liquids, sprays, granules, and foggers)
• Over-the-counter medicated flea shampoos
• Topical flea and tick preventatives

How poisonous are these insecticides to dogs, cats, and other animals?

Whether or not a pyrethrin or pyrethroid product is toxic depends on the species, the concentration, and the other ingredients that make the product effective (synergists and carrier). The use of pyrethrins or pyrethroids is generally safe in dogs, but cats and fish are very sensitive to these products.

Fish may die from even the smallest exposure, so be sure to cover aquarium tanks with something non-porous, like plastic wrap, or remove the tank from any area you treat with a pyrethrin or pyrethroid product.

Cats are also very sensitive to pyrethrins and pyrethroids because they cannot metabolize (break down) these agents quickly and efficiently due to their unique liver metabolism. Life-threatening signs may be seen in cats with even a small exposure to products containing pyrethroids.

How are cats exposed to pyrethrin or pyrethroid insecticides?

Unfortunately, the most common exposure in cats is due to owner error. Some cat owners mistakenly or purposely apply a dog flea and tick product (a high concentration pyrethrin or pyrethroid product) to their cats. Never use topical dog flea and tick spot-on products on a cat without consulting your veterinarian. Always double- and triple-check what you are applying to, or using around, your cat. Never apply a “small dog” flea and tick medication to a cat.

Cats can also be exposed under these other scenarios:

• Contact with a recently treated dog. Cats living in close contact with dogs (e.g., grooming each other, sleeping next to each other) can be exposed if a dog was recently treated with a high-concentration pyrethrin or pyrethroid flea and tick preventative. It is best to separate your dog and cat until the flea-tick product is completely dry.
• Exposure to a dog flea and tick shampoo or collar. These products contain low concentrations of pyrethrins or pyrethroids, so they should only be used as directed and kept in a closed, safe place away from cats. Flea and tick shampoos or collars specifically labeled for cats are safe to use.

What are the signs of pyrethrin or pyrethroid poisoning?

Signs of pyrethrin or pyrethroid toxicity in cats are serious. Pyrethrin and pyrethroid toxicity can be fatal for cats if not treated immediately. If you notice any of the following signs in your cat, visit your veterinarian for further treatment:

• Excessive salivation (drooling)
• Agitation or restlessness
• Vomiting
• Hiding
• Incoordination or difficulty jumping, standing or walking
• Shaking, twitching, tremors
• Seizures
• Dyspnea (difficulty breathing)
• Hypothermia (low temperature) or hyperthermia (high temperature)

What should I do if my cat is showing these signs?

If you suspect that your cat is having a severe reaction to a pyrethrin or pyrethroid, bring your cat to your regular or emergency veterinarian immediately. If you’re not sure what you’re seeing, immediately call your veterinarian or Pet Poison Helpline, a 24/7 animal poison center, at 1-800-213-6680. The sooner you seek treatment, the better the prognosis and outcome for your pet.

How is pyrethrin or pyrethroid poisoning diagnosed?

Your veterinarian will make a presumptive diagnosis if there is a known or possible history of exposure to a product containing a pyrethrin or pyrethroid, coupled with the expected signs.

How is pyrethrin or pyrethroid poisoning treated?

There is no antidote for pyrethrin or pyrethroid poisoning. However, quick and effective treatment with decontamination, monitoring, and supportive care help minimize the extent and severity of signs. 

Once your cat is stable (i.e., not showing severe clinical signs), your veterinarian may bathe your cat and provide symptomatic and supportive care, depending on the signs present. In addition, your veterinary team will carefully monitor your cat’s temperature for an elevated or lowered reading. In most cases, your veterinarian will monitor bloodwork as well, to make sure blood sugar and kidney function remain normal.

What is the prognosis if a cat has severe pyrethrin or pyrethroid poisoning?

If your veterinarian can provide prompt, early treatment, the prognosis is usually good. However, if the cat develops uncontrolled neurological signs, clotting problems, or kidney failure related to seizures or elevated body temperature, then the prognosis is typically poor.

How can I protect my cat from this poisoning?

With any poisoning, rapid diagnosis and treatment is imperative.

• Be careful with topical flea and tick preventatives that you apply to your cat. Only use cat products on cats. Remember, while dog preventatives are safe for dogs, they can be very dangerous to cats.
• To prevent accidental exposure, read the directions for any product carefully before use.
• Keep your cat separate from any dogs that have been treated for 12 to 24 hours. This time allows the product to dry thoroughly. When in doubt, you can put a T-shirt on your dog to prevent accidental exposure to your cat until the product is dried.
• Be cautious about the number of different flea or tick products used on your pet, as many products are not designed to be used in combination with other products. 
• If you have a flea infestation, call your veterinarian to discuss proper and safe treatment for your pets and your environment.
• Use the appropriate flea and tick preventative for your cat’s weight range. Do not use part of a larger-sized dose, or multiple smaller-sized doses, as this may result in poisoning. When in doubt, bring your cat to the veterinarian for a weigh-in.
• Store all pyrethrin or pyrethroid products safely and out of reach of your pets.
• Never use an insecticide on a pet that is not intended to be used on animals. Even if the concentration of insecticide is low, the carriers or other components may be harmful to animals.
• Keep your cat away from any areas, both indoors and outdoors, that have been treated with a pyrethrin or pyrethroid product until it has completely dried.

Pet Poison Helpline, an animal poison center based out of Minneapolis, MN, is available 24/7 for pet owners and veterinary professionals that require assistance treating a potentially poisoned pet. The staff provides treatment advice for poisoning cases of all species, including dogs, cats, birds, small mammals, large animals, and exotic species. As the most cost-effective option for animal poison control care, Pet Poison Helpline’s per-incident fee includes follow-up consultations for the duration of the poison case. Pet Poison Helpline is available in North America by calling 800-213-6680. Additional information can be found online at www.petpoisonhelpline.com.