Oral Pill (Program , Capstar , Sentinel ) These products prevent flea eggs from hatching when administered orally to pets once a month at mealtime. Dogs are fed Program in tablet form, whereas cats are fed a liquid suspension mixed with their food. Different tablet sizes and suspension doses are prescribed according to the weight of the animal. When an adult female flea bites a Program treated dog or cat, the flea ingests the active ingredient (lufenuron) which then passes into her eggs and prevents them from hatching. A companion product, Sentinel™, contains both the flea control ingredient and heartworm medication all in one dosage.