Information about Fipronil

Fipronil is a broad-use insecticide that belongs to the phenylpyrazole chemical family. Fipronil is a broad-spectrum insecticide that disrupts the insect central nervous system by blocking the passage of chloride ions through the GABA receptor and glutamate-gated chloride (GluCl) channels, components of the central nervous system. This causes hyperexcitation of contaminated insects' nerves and muscles. Specificity of fipronil on insects may come from a better efficacy on GABA receptor, but also because GluCl channels do not exist in mammals.
Fipronil is a slow acting poison. When used as bait, it allows the poisoned insect time to return to the colony or harborage. In cockroaches, the feces and carcass can contain sufficient residual pesticide to kill others in the same nesting site[citation needed]. In ants, the sharing of the bait among colony members assists in the spreading of the poison throughout the colony[citation needed]. With the cascading effect, the projected kill rate is about 95% in three days for ants and cockroaches[citation needed]. Fipronil serves as a good bait toxin not only because of its slow action, but also because most, if not all, of the target insects do not find it offensive or repulsive.[citation needed]
Toxic baiting with fipronil has also been shown to be extremely effective in locally eliminating German wasps (commonly called yellow jackets in North America). All colonies within foraging range are completely eliminated within one week.
Wildlife impacts include the following:
Fipronil is highly toxic to fish and aquatic invertebrates. Its tendency to bind to sediments and its low water solubility may reduce the potential hazard to aquatic wildlife.
Fipronil is toxic to bees and should not be applied to vegetation when bees are foraging.
Fipronil has been found to be highly toxic to upland game birds, but is practically nontoxic to waterfowl and other bird species. One of the metabolites of fipronil has a higher toxicity to birds than the parent compound itself.
Fipronil is also used as the active ingredient in flea control products for pets, field pest control for corn, golf courses and commercial turf, although flea populations appear to be developing a genetic resistance to its effects.
Fipronil acts by binding to an allosteric site of GABAA receptors and GluCl receptor (of the insect), a form of noncompetitive inhibition.