Used in antiviral therapy, particularly against RNA viruses such as SARS-CoV-2. It acts as a prodrug that, once metabolized in the body, inhibits viral RNA polymerase by causing delayed chain termination during replication. This interference reduces viral load and slows disease progression. It has been applied in the treatment of COVID-19, especially in hospitalized patients requiring oxygen support, to shorten recovery time and reduce the risk of severe outcomes. Its mechanism also shows activity against other coronaviruses and emerging RNA viruses, making it a candidate for broad-spectrum antiviral development.