Although hydroxychloroquine and chloroquine are not recommended and are potentially harmful in COVID-19, these agents may also antagonize the antiviral effect of remdesivir.51 A published case report highlights that remdesivir’s P-gp–mediated efflux from hepatocytes may be impaired by P-gp inhibitors, potentially contributing to an enhanced hepatotoxic effect of remdesivir.52 There is also a possible risk for increased QTc interval with remdesivir.53 Thus, QTc interval monitoring is recommended when there is a DDI with another agent that can prolong QTc. This evidence concerns the gene PGP and COVID-19.