Side Effects of Frontline in Cats

Frontline is the brand name of fipronil, which is a medication that is used to control fleas and ticks in cats. It can also be used to treat walking dandruff mite and chewing lice. This prescription medication is applied to the cat's skin and coat, and while it is typically harmless, it can be important to know about the side effects before you administer it to your cat.

  1. Irritation

    • Because Frontline is a drug that is applied to the skin, it can irritate the skin on animals that are particularly sensitive. One of the advantages is that Frontline only needs to be applied once a month, which can keep the sensitivity down to a tolerable level. Signs of irritation include a cat that constantly bites or scratches at its skin. Typically, irritation will subside within a few days.

    Hives

    • Hives show up as swollen, red patches on a cat's skin. Hives might be dry, or they might be damp and oozing to the touch. Their appearance is a sign that a cat may be allergic to Frontline, which can be a problem for cats that are extra sensitive. Hives have a welted appearance, and the hair that grows on the hives may stand straight up.

    Swelling

    • Swelling, especially through the face, is a sign that the cat might be allergic to Frontline. While it is rare, a persistent reaction that lasts for more than a few days may be a sign that the cat needs to be taken to the veterinarian. Swelling may be mild, or it might be severe enough that the cat cannot see because it is face is too swollen.

    Rashes

    • Rashes are small, bright red welts that can appear on your cat's skin if it is irritated by Frontline. Rashes are itchy, and they can cover any portion of the cat's body. The cat will likely scratch at the rash, which in turn can make the rash even more severe. Some cats will even bite or chew the rashes so much that they begin to bleed. Rashes can be hazardous to cats because if they become inflamed or irritated, they can become infected.