Veterinarian's Review: The active ingredient in Program Flea Killer, Lufenuron, presents a biological solution to a biological problem: it is an insect development inhibitor (IDI) that works in the bloodstream and interrupts the life cycle of the flea to prevent the continuing reproduction of new generations.
Ingredients: Lufenuron
Drug Side Effects: Program flea killer can lead to an upset stomach, causing vomiting, diarrhea, and loss of appetite; it can also have an adverse effect on the skin, leading to pruritus (itchiness, urticaria (hives), and skin congestion (redness). Other side effects include depression and lethargy.