An antiparasiticide member of the avermectin group, this semisynthetic veterinary drug is a modified version of doramectin; a macrocyclic lactone, this isolate results in the lowest toxicity in Collies; usually applied topically on a monthly basis, indications are for prevention of Dirofilaria immitis, Ctenocephalides felis, Sarcoptes scabeii, Dermacentro variabilis, Otodectes cynotis, and in cats, also Ancylostoma tubaeforme and Toxocara cati; commercial solution is flammable. Acts by enhancing gamma amino butyric acid release at the presynaptic membrane and enhancing chloride permeabilty, resulting in parasite paralysis and death. Not effective against flukes or tapeworms.