Description

Molvir is the brand name for the generic drug molnupiravir. It is an oral, antiviral medication that is a prodrug of N4-hydroxycytidine (NHC). This means it is a substance that is metabolized within the body to become its active form, NHC. It is an orally active drug, developed to treat certain RNA viruses.

Indication

Molvir (molnupiravir) is indicated for the treatment of mild to moderate COVID-19 in adults who have a positive SARS-CoV-2 diagnostic test and are at a high risk for developing severe illness, including hospitalization or death. It is used in non-hospitalized patients and must be initiated within 5 days of symptom onset. It is not a substitute for COVID-19 vaccination.

Mechanism of Action

Molnupiravir works by a unique mechanism known as “lethal mutagenesis” or “viral error catastrophe.” The process is as follows:

1. After being ingested, molnupiravir is converted into its active form, NHC, which is then phosphorylated to its active 5′-triphosphate form (NHC-TP).
2. NHC-TP is a ribonucleoside analog that mimics both cytidine (C) and uridine (U), which are natural building blocks of RNA.
3. During viral replication, the SARS-CoV-2 virus’s RNA-dependent RNA polymerase (RdRp) enzyme mistakenly incorporates NHC-TP into the newly made RNA strand instead of the correct C or U.
4. Because NHC-TP can mimic both C and U, it causes a high rate of mutations when the new viral RNA is transcribed and copied.
5. These mutations accumulate to the point where the viral genome becomes too flawed to function, effectively stopping the virus from replicating and leading to its extinction within the host’s body.