Molnupiravir (EIDD-2801, MK-4482) is the isopropylester prodrug of [N4-hydroxycytidine].[A193014,A193026] With improved oral bioavailability in non-human primates, it is hydrolyzed _in vivo_, and distributes into tissues where it becomes the active 5’-triphos…

N4-Hydroxyctidine, or EIDD-1931, is a ribonucleoside analog which induces mutations in RNA virions.[A193008,A193011] N4-hydroxycytidine was first described in the literature in 1980 as a potent mutagen of bacteria and phage.[A193023] It has shown antiviral ac…