Amantadine Treatment for People with COVID-19
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7290190/
Amantadine has been used as an antiviral therapy against the influenza A virus, the proposed mechanism is that the drug blocks the early stage of viral replication. When the viral particle enters the cell, an endosome is formed, which has an acid pH of 5, the proton channel is formed by the M2 protein, which carries protons into the interior of the virion. Amantadine by its lipophilic nature is able to cross the endosome membrane and interrupt the release of the virion into the cell.
Similarly, amantadine may enter the E-channel of the coronavirus preventing the release of the viral nucleus into the cell. Docking studies suggest how amantadine would interact with the amino acids ALA22 and PHE26, blocking the proton channel (6).