Waiting for the vaccine and/or the best antiviral treatment for coronavirus infection disease 2019 (COVID-19), after its outbreak in China at the beginning of 2020 and its viral diffusion around the world in the following weeks, several drugs have been suggested for their potential adjuvant support against infection. Several drugs have been suggested to have a potential ancillary antiviral role. Circulating proteins, in particular proteases and peptidases regulated by drug functions, may interact with well-known drugs like anticoagulants, antihypertensives, antiserotoninergics, and so also with viral proteases. We here report a brief list of these drugs (i.e., heparinoids, flavonoids, antiplatelets, anticoagulants) that may interact with COVID-19.