Ivermectin is a large lipophilic molecule that acts as a positive allosteric regulator of several ligand-gated channels including the glutamate-gated chloride channel, gamma aminobutyric acid type-A receptor, glycine receptor, neuronal alpha7-nicotinic receptor and purinergic P2X4 receptor. This review summarizes what is currently known about ivermectin binding and modulation of Cys-loop receptor family of ligand-gated ion channels and what are the critical structural determinants underlying potentiation of the P2X4 receptor channel.