Direct from official FDA site.
Used to treat several neglected tropical diseases, including onchocerciasis, helminthiases, and scabies. For these indications, ivermectin has been widely used and is generally well-tolerated.
Ivermectin is not approved by the FDA for the treatment of any viral infection.
Ivermectin Proposed Mechanism Of Action
Proposed Mechanism of Action and Rationale for Use in Patients With COVID-19 (in vitro studies) suggest that ivermectin acts by, Inhibiting host importin nuclear transport proteins. Interfere with SARS-CoV-2 spike protein attachment to the human cell membrane. Some studies of ivermectin have also reported potential anti-inflammatory properties. Shown to inhibit replication of SARS-CoV-2 in cell cultures.