Dangers Of Using Canine Flea & Tick Medications On Cats

Article by Fiona Lee for PetsBest

When you have both cats and dogs, it’s easier than you think for flea and tick medications to mistakenly end up where they shouldn’t. Even worse, using flea and tick preventatives made for a dog on a cat can be fatal. While it might seem harmless, using canine parasite preventatives on cats can lead to a veterinary emergency. Sadly, as many emergency veterinarians can attest, it occurs more often than you might assume. In this article, we’ll cover the danger in giving your cat a flea or tick product intended for a dog, and what course of action to take if your cat is exposed to these products.

Topical Flea and Tick Control Products Dangerous for Cats

Topical or spot-on flea treatments are among the most popular products available. They are not all the same and some can be very toxic to cats. Brands like Vectra 3D, K9 Advantix, Bio Spot-on, and some Hartz products contain permethrin, which is extremely toxic to cats (Handley, n.d.). The reason for this is because cats lack enzymes in their liver to effectively break down certain chemicals, permethrin being one of them.

Poisoning can occur by applying a solution with permethrin on your cat, or if your cat comes in contact with a dog that has recently been treated with a permethrin-based product. For this reason, you should keep a cat away from a dog that has been treated with a flea and tick medication containing permethrin for 72 hours. Even a small dose of permethrin can adversely affect your cat’s health.

Permethrin exposure affects a cat’s nervous system and can cause the following symptoms:

  • Agitation
  • Drooling or vomiting
  • Lethargy
  • Tremors
  • Shaking
  • Twitching
  • Oversensitivity to touch
  • Lack of coordination

If you believe your cat has been exposed to permethrin, contact your veterinarian immediately or take them to an emergency veterinarian. The sooner you act, the greater the chances of effectively treating the situation and the less expensive the care will be. Most cats that receive treatment make a complete recovery, but death can occur in certain cases.

Other oral products work on different flea life stages, and can include such brands as Bravecto (Fluralaner, this is not labeled for use in cats) and Program (Lufenuron, which is labeled for safe use in cats).

Cat Safe Flea and Tick Medications

While dog-specific topical medications pose a significant risk to cats, there are several made for cats that are very safe. Frontline, which has a main active ingredient called fipronil, is available over the counter and is safe for cats when the cat-specific product is purchased. Revolution, which includes selamectin, is available by veterinary prescription only and is very safe for cats. Advantage, which is the name brand for imidacloprid, is available over the counter and is safe as long as the cat version of the drug is used.

Tick and Flea Collars for Cats

Most dog tick and flea collars contain permethrins or organophosphates and work by repelling insects. As a result, they are very toxic to cats and in some cases can be fatal. Tick-only preventative collars, such as Scalibor (Deltamethrin) or Preventic (Amitraz) are meant for use on dogs only and are lethal to cats. Cat safe flea and tick collars range from options that use imidacloprid (Seresto) to plant based essential oil options. Always consult with your veterinarian before using any of these options on your cat.

Oral Prescription Medications for Preventing Parasites

All oral preventatives are available by veterinary prescription only. Some oral medications are adulticides, such as Capstar (Nitenpyram) or Comfortis (Spinosad). These are both safe products for cats. Other oral products work on different flea life stages and can include brands such as Bravecto (made with fluralaner and not for use in cats) and Program (made with lufenuron, which is safe for use in cats). It should go without saying that any oral preventatives designed for dogs should not be administered to cats.

The Bottom Line

The takeaway is to only use products that are intended for cats and use them as directed on the label. Just because a product is available in cat and dog formulations doesn’t mean they are interchangeable. Remember, a small dog dose may be very different from the cat dose, even if those animals have the same body size. Lastly, be certain of your pet’s weight before applying any medication. In general, it is a good idea to consult your veterinarian to help with choosing a flea or tick product. Not only will your veterinarian direct you to a safe product, but most prescription products are more effective than over-the-counter solutions.


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