Eprinomectin is a mixture of eprinomectins B1a and B1b in a 9:1 ratio, produced from a mixture of avermectin B1a and B1b. Eprinomectin is used commercially as a topical endectocide (insecticide, miticide and nematocide) for cattle, including lactating dairy cows. Like all avermectins and milbemycins, eprinomectin acts by binding to parasite glutamate-gated chloride ion channels and disrupts neurotransmission leading to paralysis and death of the parasite, mite or insect.