Afoxolaner (brand name NexGard) is a member of an isoxazoline class of compounds, which is used to kill adult fleas and is indicated for the treatment and prevention of flea infestations, and the treatment and control of Black-legged tick, American Dog tick, Lone Star tick, and Brown dog tick infestations in dogs and puppies. Afoxolaner is a member of the isoxazoline family, shown to bind at a binding site to inhibit insect and acarine ligand-gated chloride channels, in particular those gated by the neurotransmitter gamma-aminobutyric acid (GABA), thereby blocking pre- and post-synaptic transfer of chloride ions across cell membranes. Afoxolaner blocks native and expressed insect GABA-gated chloride channels with nanomolar potency. Prolonged afoxolaner-induced hyperexcitation results in uncontrolled activity of the central nervous system and death of insects and acarines.