Ivermectin (, EYE-vər-MEK-tin) is an antiparasitic drug. After its discovery in 1975, its first uses were in veterinary medicine to prevent and treat heartworm and acariasis. Approved for human use in 1987, today it is used to treat infestations including head lice, scabies, river blindness (onchocerciasis), strongyloidiasis, trichuriasis, ascariasis and lymphatic filariasis. It works through many mechanisms to kill the targeted parasites, and can be taken orally, or applied to the skin for external infestations. It belongs to the avermectin family of medications.William Campbell and Satoshi Ōmura won the 2015 Nobel Prize in Physiology or Medicine for its discovery and applications. It is on the World Health Organizations List of Essential Medicines, and is approved by the U.S. Food and Drug Administration as an antiparasitic agent. In 2018, it was the 420th most commonly prescribed medication in the United States, with more than 100,000 prescriptions. It is available as a generic medicine.During the COVID-19 pandemic, misinformation has been widely spread claiming that ivermectin is beneficial for treating and preventing COVID-19. Such claims are not backed by credible scientific evidence. Multiple major health organizations, including the Food and Drug Administration, U.S. Centers for Disease Control, the European Medicines Agency, and the World Health Organization have stated that ivermectin is not authorized or approved to treat COVID-19. Medical uses
Ivermectin is used to treat human diseases caused by roundworms and ectoparasites.
Use in turtles is particularly contraindicated.A characteristic of the antinematodal action of ivermectin is its potency: for instance, to combat Dirofilaria immitis in dogs, ivermectin is effective at 0.001 milligram per kilogram of body weight when administered orally.For dogs, the insecticide spinosad may have the effect of increasing the toxicity of ivermectin. Pharmacology
Mechanism of action
Ivermectin and its related drugs act by interfering with the nerve and muscle functions of helminths and insects. The drug binds to glutamate-gated chloride channels common to invertebrate nerve and muscle cells. The binding pushes the channels open, which increases the flow of chloride ions and hyper-polarizes the cell membranes, paralyzing and killing the invertebrate. Ivermectin is safe for mammals (at the normal therapeutic doses used to cure parasite infections) because mammalian glutamate-gated chloride channels only occur in the brain and spinal cord: the causative avermectins usually do not cross the blood–brain barrier, and are unlikely to bind to other mammalian ligand-gated channels. Pharmacokinetics
Ivermectin can be given by mouth, topically, or via injection. It does not readily cross the blood–brain barrier of mammals due to the presence of P-glycoprotein (the MDR1 gene mutation affects the function of this protein). Crossing may still become significant if ivermectin is given at high doses, in which case brain levels peak 2–5 hours after administration. In contrast to mammals, ivermectin can cross the blood–brain barrier in tortoises, often with fatal consequences. Chemistry
Fermentation of Streptomyces avermitilis yields eight closely related avermectin homologues, of which B1a and B1b form the bulk of the products isolated.