Ivermectin is used to treat human diseases caused by roundworms and ectoparasites.
For river blindness (onchocerciasis) and lymphatic filariasis, ivermectin is typically given as part of mass drug administration campaigns that distribute the drug to all members of a community affected by the disease. For river blindness, a single oral dose of ivermectin (150 micrograms per kilogram of body weight) clears the body of larval Onchocerca volvulus worms for several months, preventing transmission and disease progression. Adult worms survive in the skin and eventually recover to produce larval worms again; to keep the worms at bay, ivermectin is given at least once per year for the 10–15-year lifespan of the adult worms. For lymphatic filariasis, oral ivermectin (200 micrograms per kilogram body weight) is part of a combination treatment given annually: ivermectin, diethylcarbamazine citrate and albendazole in places without onchocerciasis; and ivermectin and albendazole in places with onchocerciasis.
The World Health Organization (WHO) considers ivermectin the drug of choice for strongyloidiasis. Most cases are treated with two daily doses of oral ivermectin (200 μg per kg body weight), while severe infections are treated with five to seven days of ivermectin. Ivermectin is also the primary treatment for Mansonella ozzardi and cutaneous larva migrans. The U.S. Centers for Disease Control and Prevention (CDC) recommends ivermectin, albendazole, or mebendazole as treatments for ascariasis. Ivermectin is sometimes added to albendazole or mebendazole for whipworm treatment, and is considered a second-line treatment for gnathostomiasis.
Mites and insects
Ivermectin is also used to treat infection with parasitic arthropods. Scabies – infestation with the mite Sarcoptes scabiei – is most commonly treated with topical permethrin or oral ivermectin. For most scabies cases, ivermectin is used in a two dose regimen: a first dose kills the active mites, but not their eggs. Over the next week, the eggs hatch, and a second dose kills the newly hatched mites. For severe “crusted scabies”, the U.S. Centers for Disease Control and Prevention (CDC) recommends up to seven doses of ivermectin over the course of a month, along with a topical antiparasitic. Both head lice and pubic lice can be treated with oral ivermectin, an ivermectin lotion applied directly to the affected area, or various other insecticides. Ivermectin is also used to treat rosacea and blepharitis, both of which can be caused or exacerbated by Demodex folliculorum mites.