Ivermectin B1B (dihydroavermectin B1b) is the minor component (<10%) of the commercial anthelmintic, ivermectin. Members of the avermectin/milbemycin anthelmintic class exert their anthelmintic effects by binding to glutamate-gated chloride channels expressed on nematode neurons and pharyngeal muscle cells. The avermectin/milbemycins are also potent insecticides. In vitro, the B1b (25-isopropyl) analog is slightly more potent than the 25-sec-butyl (B1a) analog as an inhibitor of nematode larval development and paralysis, and also a more sensitive probe for ivermectin resistance.

22,23-dihydro-avermectin B1a is a major form of Ivermectin mixture (more than 90%). It is a broad-spectrum anthelmintic (worms), microfilaricide (heartworms), and miticide (mites) drug, used for horses, cattle, pigs, household pets. Ivermectin used in humans, especially for river blindness. Ivermectin binds selectively and with high affinity to glutamate-gated chloride ion channels in invertebrate muscle and nerve cells of the microfilaria.

Ivermectin is a broad-spectrum anti-parasite medication. It was first marketed under the name Stromectol® and used against worms (except tapeworms), but, in 2012, it was approved for the topical treatment of head lice infestations in patients 6 months of age and older, and marketed under the name Sklice™ as well. Ivermectin is mainly used in humans in the treatment of onchocerciasis but is also effective against other worm infestations (such as strongyloidiasis, ascariasis, trichuriasis, and enterobiasis). Ivermectin binds selectively and with high affinity to glutamate-gated chloride ion channels in invertebrate muscle and nerve cells of the microfilaria. This binding causes an increase in the permeability of the cell membrane to chloride ions and results in hyperpolarization of the cell, leading to paralysis and death of the parasite. Ivermectin also is believed to act as an agonist of the neurotransmitter gamma-aminobutyric acid (GABA), thereby disrupting GABA-mediated central nervous system (CNS) neurosynaptic transmission. Ivermectin may also impair the normal intrauterine development of O. volvulus microfilariae and may inhibit their release from the uteri of gravid female worms. It is sold under brand names Heartgard, Sklice and Stromectol in the United States, Ivomec worldwide by Merial Animal Health, Mectizan in Canada by Merck, Iver-DT in Nepal by Alive Pharmaceutical and Ivexterm in Mexico by Valeant Pharmaceuticals International. In Southeast Asian countries, it is marketed by Delta Pharma Ltd. under the trade name Scabo 6.