The first active ingredient is imidacloprid, which acts on the nervous system of the flea to cause paralysis and subsequent death. Within 12 hours of application, 98-100 percent of fleas are dead. The second active ingredient, pyriproxyfen, is an insect growth regulator. Once a female flea lays her eggs, pyriproxyfen works to prevent the eggs from hatching, ending the flea life cycle. Also, the active ingredient in Advantage II kills through contact, which means that fleas don't have to bite your pet to die.
Imidacloprid: Imidacloprid is an ectoparasiticide, an antiparasitic agent that targets parasites living primarily on the surface of a host. Chemically classified as a chloronicotinyl nitroguanidine, imidacloprid inhibits neurotransmitter transmission in insects, resulting in paralysis and death.
Benefits: Imidacloprid exhibits both adulticide and larvicidal flea efficacy; it not only kills adult fleas and larvae on your pet, but it also kills larval stages in your pet's immediate surroundings.
Main Purpose: To kill fleas at all stages of their life cycles and stop them from being able to move or feed.
Pyriproxyfen: Pyriproxyfen, the added compound in Advantage II, is a pyridine-based pesticide. A juvenile hormone analog, it interferes with the hormone signaling of growing insects, so that insects in immature stages are unable to mature. Additionally, a female insect that touches the toxin will produce eggs that will not hatch.
Benefits: Pyriproxyfen provides an added layer of protection for pets and their surroundings. It interrupts the flea life cycle at multiple stages, halting the growth and development of insect eggs and larvae and preventing reinfestation. Main Purpose: To prevent flea eggs from hatching and larvae from growing.