Bayer makes two different flea control products that can easily be confused with one another, leading to potentially lethal complications in our feline family members. Advantage has formulations approved for both dogs and cats, while the product Advantix is intended for use in dogs only. Advantix causes permethrin toxicity in cats, which is a common emergency I see, especially during the spring and summer months, when fleas are at their peak of peskiness. 

What exactly is the difference?
Advantage is a topical solution that can be applied to either your dog or cat’s skin once per month for flea prevention, and it contains the active ingredient imidacloprid.

Advantix is also a topical solution for the treatment and prevention of fleas, ticks, biting flies, mosquitoes and lice on dogs. The product’s active ingredients are imidacloprid and permethrin. It is the addition of permethrin to the recipe that makes the deadly difference.

Dogs can metabolize permethrin effectively, resulting in a safe product for them. However, cats cannot metabolize this ingredient, and will suffer from toxic effects if exposed. Cats are exposed to Advantix in a variety of ways, including direct application, close contact with a dog who has been treated within 48 hours, or if they have groomed a doggy pal’s fur after an application.

What are the symptoms?
Symptoms in cats will generally manifest within a few hours, but it can take up to three days following Advantix exposure or application. Symptoms include tremors and twitching (sometimes just the ear tips), hyperexcitability, drooling, depression, loss of coordination, vomiting, seizures, loss of appetite and, potentially, death, if not treated. One of the major concerns is an extreme elevation in body temperature from the continuous muscle activity due to tremoring.

What is the treatment?
Treatment consists of decontamination of the skin with a bath, tremor and/or seizure control and supportive care. Medications are given as needed by an intravenous injection to control these clinical signs. General supportive care takes the form of intravenous fluids to keep the cat hydrated, as well as vital-sign monitoring and providing a safe environment so the cat does not harm him or herself during the period of incoordination and disorientation. Clinical signs of tremors generally last for 12 to 24 hours but may persist for up to 48 to 72 hours.

Prognosis for recovery is excellent with early treatment.

Prevention tips
If you share your home with both dogs and cats, it is not advisable that you treat your dog’s parasites with Advantix mainly because accidents can occur. I often hear a distressed owner say that they “accidentally” applied the wrong one, so I feel that it is best just to take that risk out of the equation, especially when there are so many other flea control options available.

If you do use canine Advantix in a home with cats, apply the medicine to your dog while your cat does not have access to the area or to the dog and allow for the medicine to fully absorb into your dog’s skin—when you can no longer visibly see the oily medication on the fur—before allowing your cat back into the same room. I have treated cats that were obsessive groomers and decided the fur between “their” dog’s shoulder blades needed to be cleaned.

And lastly, always double-check labels and read all the fine print; you can even have someone just “double-check you” as another safety precaution.