Side Effects of Feline Frontline

Frontline―which also goes by the generic name of fipronil―is a topical flea treatment for both felines and canines. Specifically, Frontline is used to prevent flea and tick infestations from occurring or reoccurring, and can also kill fleas and ticks on the cat within 24 hours of application. Unfortunately, as with any medication, there are potential side effects.

  1. Application

    • According to package directions, Frontline for cats is applied between the shoulder blades. Dosages are specific to the weight of the cat.

    Irritation

    • One of the most common side effects of Frontline is irritation at the site of application. For the majority of cats, irritation is only temporary. However, if the application site remains irritated for several days, veterinary care should be sought immediately.

    Redness

    • Redness is another side effect that might occur at the application site. Fortunately, redness is temporary and is not considered to be life-threatening.

    Itching

    • The application site might become itchy, especially if the cat has a hypersensitivity to the product. Itching can be mild to severe; however if itching persists, veterinary care should be sought immediately.

    Infections

    • As with any irritation to the skin, secondary infections are a possibility. Cats who scratch excessively at their skin can cause open wounds and sores in which bacteria, fungi or viruses can enter, causing an infection. If an infection occurs, seek the help of a veterinarian immediately.

    Hypersalivation

    • If the cat accidentally licks any of the product before it dries, it could cause hypersalivation―better known as drooling. If drooling persists, seek veterinary care immediately, as it might be a sign of neurological issues. Hypersalivation is one of the more rare side effects of Frontline.

    Hair Loss

    • Some cats can suffer from hair loss--either around the application site or in areas all over--following application.

    Scaly Skin

    • Some cats might also suffer from scaly skin, which can be accompanied by itching, redness or other symptoms of irritation. Scaling can occur at the site of application or all over the body.

    Vomiting

    • Vomiting can occur when Frontline is applied. If vomiting is persistent, the cat should be brought to a veterinarian immediately.

    Neurological Signs

    • In rare instances, cats can suffer from various neurological problems. These issues are reversible and can include depression and nervousness or other nervous behaviors, such as hiding.

    Hyperesthesia

    • Hyperesthesia is a condition in which the cat suffers from sudden bouts of unusual behavior. This can include becoming hyperactive or more aggressive. Additional symptoms of hyperesthesia include frantic grooming, fixation with the tail, large pupils, tail swishing, skin rippling, hallucinations, vocalization and sudden mood swings.