Toxicology Brief: The 10 most common toxicoses in cats
Cats are sensitive to many toxic agents, sometimes in ways unique to their species. In addition, cats are less likely than dogs to expose themselves through curious ingestions, but cats will nibble on potentially deadly agents, such as lilies. Cats also can jump to high places and obtain materials assumed to be out of reach. And because of their grooming behavior, cats with dermal exposure are likely to receive an oral dose as well.
In this article, we describe 10 common toxicoses in cats. The agents discussed were selected based on the 10 most frequent feline exposures reported to the ASPCA Animal Poison Control Center (APCC) in the past four years.
1 Canine permethrin insecticidesThe topical application of a permethrin spot-on or dip product labeled for use only in dogs can lead to tremors and seizures in cats. These products, which generally contain 45% or 65% permethrin in spot-ons and 3% or more permethrin in dips, are applied to cats accidentally or by individuals who ignore the warnings on the label. In some instances, cats have developed signs of permethrin toxicosis after being in close contact with (sleeping near or grooming) a dog recently treated with a permethrin spot-on product. Initial signs may appear within a few hours but can take 24 to 72 hours to manifest. Full-body tremors are the most common finding, although seizures may also occur.1 Other pyrethroids, including phenothrin and etofenprox, can cause a similar syndrome in cats when used at high concentrations.2
Treatment consists of bathing the cat in a liquid hand dishwashing detergent (e.g. Dawn Dishwashing Liquid—Procter & Gamble) to remove the sebum in which the product is distributed. If the cat is symptomatic, delay the bath until the tremors have been controlled. The tremors are best treated with slow intravenous boluses of methocarbamol (Robaxin-V—Fort Dodge Animal Health; total initial dose 55 to 220 mg/kg).1 Repeat the methocarbamol as needed, but do not exceed a dose of 330 mg/kg/day or respiratory depression may occur.3 If methocarbamol is not effective, then barbiturates, propofol, or both can be used. Diazepam is generally ineffective for the tremors but should be used if seizures are present.
Additional care should include monitoring the patient's body temperature and administering intravenous fluids to protect the kidneys from myoglobinuria due to muscle breakdown. Atropine is not antidotal for permethrin; no true antidote exists. The prognosis is generally good with aggressive supportive care.
2 Other topical insecticides
Besides permethrin products, many other flea control products are on the market today. Topical flea control products commonly include insect growth regulators such as s-methoprene and pyriproxyfen, which have low oral and dermal toxic potential in mammals. Insecticide ingredients may include organophosphates or carbamates, pyrethroids, imidacloprid, fipronil, and selamectin, all of which when used appropriately (including low-concentration pyrethroid products) have a low risk of causing serious problems.4,5
In general, topical flea control products applied according to label directions will not cause systemic effects in cats.4,5 Any topically applied product can cause either dermal irritation or a dermal hypersensitivity-like reaction. If dermal signs appear, wash the product off with a mild detergent. If the irritation is localized, the contents of a vitamin E capsule or a corticosteroid cream can be applied. If the irritation is more widespread, corticosteroids or antihistamines may be used systemically.
If a cat licks a topically applied product, a taste reaction— characterized by hypersalivation, agitation, and occasionally vomiting—may develop. These signs are simply a reaction to the bitter taste and can sometimes be quite dramatic. Removing the product from the tongue by giving the cat milk or liquid from a tuna fish can should resolve the signs.