|Systematic (IUPAC) name|
|Ivermectin (22,23-dihydroavermectin B1a + 22,23-dihydroavermectin B1b)|
|ATC code||P02 QP54 QS02|
C47H72O14 (22,23-dihydroavermectin B1b)
|Mol. mass||875.10 g/mol|
|Half life||18 hours|
|Excretion||feces; <1% urine|
|Pregnancy cat.||B3(AU) C(US)|
Ivermectin (22,23-dihydroavermectin B1a + 22,23-dihydroavermectin B1b) is a broad-spectrum antiparasitic medication.
Ivermectin, under the brand name Mectizan, is currently being used to help eliminate river blindness (onchocerciasis) in the Americas and stop transmission of lymphatic filariasis and onchocerciasis around the world.   Currently, large amounts of Ivermectin are donated by Merck to fight river blindness in countries that are unable to afford the drug . The disease is endemic in 30 African countries, 6 Latin American countries and Yemen, according to studies conducted by the World Health Organization.  The drug rapidly kills microfilariae but not the adult worms. A single oral dose of ivermectin, taken annually for the 10-15 year life span of the adult worms, is all that is needed to protect the individual from onchocerciasis. 
Ivermectin is also used in veterinary medicine, particularly for horses and dogs. It is sometimes mixed with other medications to reach a wide spectrum of animal parasites. Some collie breeds (especially the Rough Collie and the Smooth Collie) are affected by a genetic defect, a mutation within the MDR1 gene. Affected dogs are very sensitive to some drugs, such as Ivermectin, as well as to some antibiotics, opioids and steroids – over 100 drugs in total.
Ivermectin and other avermectins (insecticides most frequently used in home-use ant baits) are macrocyclic lactones derived from the bacterium Streptomyces avermitilis. Ivermectin kills by interfering with nervous system and muscle function, in particular by enhancing inhibitory neurotransmission.
The drug binds and activates glutamate-gated chloride channels (GluCls). GluCls are invertebrate-specific members of the Cys-loop family of ligand-gated ion channels present in neurons and myocytes.
Ivermectin can be given either per os or parenterally. It does not readily cross the blood-brain barrier of mammals, although crossing may still become significant if ivermectin is given at high doses (in which case, brain levels peak 2-5 hours after administration).
The main concern is neurotoxicity, which in most mammalian species may manifest as CNS depression, and consequent ataxia, as might be expected from potentiation of inhibitory GABA-ergic synapses
Field studies have demonstrated that the dung of animals treated with ivermectin supports a significantly reduced diversity of invertebrates, and that the dung persists for longer.
Ivermectin is a broad-spectrum antiparasitic agent. It is mainly used in humans in the treatment of onchocerciasis, but is also effective against other worm infestations (such as strongyloidiasis, ascariasis, trichuriasis, filariasis and enterobiasis). More recent evidence supports its off-label use in the treatment of mites such as scabies, usually limited to cases that prove resistant to topical treatments and/or who present in advanced state (such as Norwegian scabies).