#2 REVOLUTION (For dogs 6 weeks of age and older, and no weight requirement) - Revolution is a safe and simple monthly topical medication used to protect your pet from heartworms, fleas, and ear mites. It also protects dogs from ticks and sarcoptic mange and cats from roundworms and hookworms. Revolution for Dogs and Cats requires a prescription from your veterinarian. Revolution is a topical parasiticide applied once a month for the prevention of heartworm disease in dogs and cats. Revolution is also used on dogs for the treatment or prevention of fleas, the American Dog Tick, ear mites, and canine sarcoptic mange. Revolution works by penetrating the skin and entering your pet's bloodstream. Concentrations of selamectin, the active ingredient, in the tissue and bloodstream prevent heartworm disease. Selamectin also redistributes into the skin from the bloodstream and kills adult fleas, American dog ticks, and ear mites, and prevents flea eggs from hatching. It is also an anthelmintic, which means it fights to expel parasitic worms. Parasites ingest the drug when they feed on the animal's blood. Revolution is safe for pregnant and lactating pets. Do not apply Revolution to your pet if already giving an alternate heartworm medication. When switching from another heartworm medication, begin Revolution when the next dose of the heartworm medication is due.