Virtual screening identified the serotonin antagonist cinanserin (150, Figure 35) as a potential inhibitor of Mpro. It had previously shown activity against SARS‐CoV‐1 Mpro with an IC50 value of 5 µM. 190  Subsequent tests revealed its anti‐SARS‐CoV‐2 activity (EC50, 20.6 µM) and an IC50 value of 125 µM (SARS‐CoV‐2 Mpro).