Ivermectin, a member of the Avermectin class, causes death of parasites, primarily through binding selectively and with high affinity to glutamate-gated chloride channels, which occur in invertebrate nerve and muscle cells.This leads to an increase in the permeability of the cell membrane to chloride ions with hyperpolarization of the nerve or muscle cell, resulting in paralysis and death of the parasite. Compounds of this class may also interact with other ligand-gated chloride channels,such as those gated by the neurotransmitter gamma-aminobutyric acid (GABA).The selective activity of compounds of this class is attributable to the fact that some mammals do not have glutamate gated chloride channels, the Avermectins have a low affinity for mammalian ligand-gated chloride channels, and Ivermectin does not readily cross the blood-brain barrier in humans.