K9 Advantix II Large Dog is a veterinarian-recommended topical spot-on treatment for large dogs weighing 21 to 55 pounds. This 8-dose supply provides 8 months of continuous monthly protection against five types of pests: fleas, ticks, mosquitoes, biting flies, and lice. No prescription is required, and the formula is safe for dogs at least 7 weeks old.

The treatment kills fleas within 12 hours of initial application, stopping existing infestations and preventing new ones by eliminating adult fleas before they can lay eggs. It also kills all life stages of fleas, including eggs, larvae, and pupae, to break the flea life cycle. K9 Advantix II repels and kills multiple tick species, including deer ticks, American dog ticks, brown dog ticks, and Lone Star ticks, helping reduce the risk of Lyme disease and other tick-borne illnesses. Monthly use helps protect against fleas that may transmit tapeworms and cause Flea Allergy Dermatitis or flea bite anemia.

The easy-to-apply spot-on formula is fragrance-free and becomes waterproof within 24 hours of application, making it suitable for active dogs. Active ingredients are imidacloprid (8.8%), permethrin (44.0%), and pyriproxyfen (0.44%), an insect growth regulator. K9 Advantix II is a trademark of Elanco or its affiliates.