K9 Advantix Flea Medicine Side Effects

K9 Advantix helps protect from diseases carried by ticks, mosquitoes, fleas and lice.
Hemera Technologies/AbleStock.com/Getty Images

A once-monthly topical application of K9 Advantix, manufactured by Bayer Animal Health, keeps your dog free from ticks, mosquitoes, fleas and lice. Its primary ingredients are the pesticides permethrin and imidacloprid. While most dogs tolerate this over-the-counter medication well, some might experience side effects. If your dog develops a bad reaction after receiving K9 Advantix, call your veterinarian.

Side Effects

The most common side effect in dogs after a K9 Advantix application is irritation at the application site -- the skin between the shoulder blades. Some dogs might appear lethargic after receiving the drug, while others start drooling. Vomiting after drug application also occurs in some cases.

K9 Advantix Contraindications

Don't put K9 Advantix on puppies under 7 weeks of age. Pregnant and nursing dogs should not receive this product. Avoid applying K9 Advantix to very old or debilitated dogs. Canines suffering from cardiac issues or kidney or liver disease should not receive this product. Don't use K9 Advantix on cats -- it can kill them. After applying the medication to your dog, keep him away from felines for at least two hours.