Permethrin's Side Effects in Dogs

Permethrin is a synthetic form of pyrethrin, a plant-derived insecticide used in topical flea and tick treatments for dogs. Products containing permethrin include K9 Advantix, ProTICall and Kiltix. Though the substance can be extremely dangerous to cats, it is usually safe for dogs if applied correctly. Side effects usually occur when you have applied too much permethrin to your dog. These effects can range from mild skin irritation to seizures. Contact your veterinarian if any of these side effects occur.

  1. Skin Irritation

    • Because permethrin is applied to the skin, it's the first area where side effects are likely to become apparent. The skin irritation may include redness, a rash, itching and discoloration and loss of hair, especially at the site of application, according to peteducation.com. If any of these side effects occurs, bathe your dog thoroughly then consult your veterinarian.

    Tremors and Seizures

    • Permethrin works on fleas and other insects by disrupting their neurological functions. In high doses, it can produce neurological problems as a side effect in dogs, as well. These symptoms can be minor, such as lethargy, or they can be serious, including tremors or seizures. These side effects need immediate attention from a veterinarian to prevent long-term injury. Petplace.com says dogs with tremors or seizures may need drugs to counteract the effects.

    Other Side Effects

    • Other side effects that your dog might experience after you administer permethrin include vomiting, diarrhea, and drooling. These side effects often occur after a dog licks the area where the permethrin has been applied, according to petplace.com.