<unk>  inhibits viral reproduction by promoting widespread mutations in the replication of viral RNA by RNA-directed RNA polymerase. It is metabolized into a ribonucleoside analog that resembles cytidine, β-D-N4-Hydroxycytidine 5′-triphosphate (also called EIDD-1931 5′-triphosphate or NHC-TP). During replication, the virus's enzyme incorporates NHC-TP into newly made RNA instead of using real cytidine. :650px<unk>  can swap between two forms (tautomers), one of which mimics cytidine (C) and the other of which mimics uridine (U). NHC-TP is not recognized as an error by the virus' proofreading exonuclease enzymes, which can replace mutated nucleotides with corrected versions. When the viral RNA polymerase attempts to copy RNA containing<unk> , it sometimes interprets it as C and sometimes as U. This causes more mutations in all downstream copies than the virus can survive, an effect called viral error catastrophe or lethal mutagenesis. 282px 282px Top, a G.molnupiravir base pair with three hydrogen bonds. Bottom, an A.molnupiravir base pair with two hydrogen bonds.<unk>  can mimic both C and U. The wiggly lines stand for the connection to the pentose sugar and point in the direction of the minor groove.
Molnupiravir
Balapiravir
Odalasvir
Saquinavir
Remdesivir
Coronavir
Favipiravir
Maribavir