If you want to learn a thing or two about killing bugs, look no further than the classic extermination PSA, Aliens. Step one: Duct-tape a bunch of different weapons together. Step two: Destroy the infestation at every life stage, from egg to queen.
Frontline Plus gets it. The chemical cocktail you apply to your furry best friend’s back uses a double tap–fipronil zaps flea and tick nervous systems, and S-methoprene keeps flea eggs from hatching–bound together with a secret blend of inert chemicals. Applied monthly, Frontline Plus should free you from using the nuclear option–flea baths. Let’s rock!
Fluffy and Spot can thank the French for the end of weekly flea baths. Almost three decades ago, chemists working for French pharma Rhone Merieux (now known as Merial) noticed that its fipronil-based flea killer was lethal for a lot longer than expected. Turns out, fipronil is fat-soluble and accumulates inside the oil glands that animals have on their skin. Once absorbed, this insecticide leaks out of the glands slowly, coating strands of your best friend’s fur. Along comes a tick or flea, jonesing for a blood fix. Instead, it rubs up against some of that fipronil-tainted fur. The poison attacks Jumpy McFlea’s nerve cells, binding to receptors meant to receive signals that keep the critter’s nerves sort of relaxed. The bug’s nervous system goes hyperactive, and within 30 minutes it convulses to death. Pauvre petite nuisance …
Tick eggs aren’t a problem for pets, since those suckers fall off before they lay eggs. But a female flea can lay about 50 eggs a day in an animal’s fur, and in the concentrations here, fipronil can’t scramble them all. So Frontline deploys this harmless-to-mammals chemical. S-methoprene seeps into the egg, where it pretends to be a hormone that keeps the bug baby from attaining its next developmental stage. Like a logic error, the chemical imposter interrupts things and baby-flea.exe crashes.
Around 80 percent of the contents of Frontline Plus are not frontline combatants. That portion consists of chemicals like glycol ether and ethanol, which keep the fipronil and S-methoprene stable. Since they’re inert, Merial doesn’t have to disclose much about these substances. One thing we do know: Without them, Frontline Plus would be less vigorous at vanquishing those tiny vampires.