Program was the first of these new generation flea control products. Its action is to interfere with the production of normal eggs within the adult female flea. Program does not kill adult fleas. It should be started prior to the advent of flea season, or if used on flea infested animals, should initially be supplemented with an insecticide. Three to four weeks are required in most cases to see an effect from Program alone, as again, it interferes with the life cycle, but does not affect adults.
Program is given orally as a tablet in dogs, or a liquid suspension in cats.
Program is now also available in an injectable form for cats which is administered every six months. It is important to treat all animals in the household, as untreated animals will serve as a source of reinfestation for treated animals. In order for Program to be correctly absorbed from the intestinal tract, it must be dissolved in fat. It is administered every thirty days, and once absorbed into the body, is stored in the fat and slowly released into the animal's bloodstream. When the adult flea takes a blood meal, the Program is taken in by the flea, and interferes with egg production.