Atovaquone is an orally active, synthetic hydroxy-naphthoquinone derivative (Figure S6) with antiparasitic activity. It was approved by the U.S. FDA in 1992 against Pneumocystis jirovecii pneumonia [215]. It has also been used to prevent and/or treat toxoplasmosis, malaria, and babesiosis [216,217,218,219]. Mechanistically, it inhibits the electron transport chain in mitochondria, leading to the inhibition of critical metabolic enzymes important for the synthesis of nucleic acids and ATP [220]. It is being evaluated in the U.S. alone (NCT04456153; n = 60) or in combination with azithromycin in an open-label, non-randomized study in COVID-19 patients at HonorHealth Clinical Research Institute, U.S. (NCT04339426; n = 25). One potential mechanism of action for atovaquone pertaining to SARS-CoV-2 is the inhibition of Mpro [221]. Another computational study suggested that it may inhibit RdRp [169]. Importantly, these computational studies are yet to be experimentally confirmed.