Lamivudine triphosphate (3TCTP), a phosphorylated form of the nucleoside analogue Lamivudine, inhibits the reverse transcriptase of HIV or HBV, blocking viral replication through chain termination. It also acts as an inhibitor of the RdRp activity of the HCVNS5B subunit. Additionally, Lamivudine triphosphate can be incorporated into nascent RNA by SARS-CoV-2 RdRp, thereby preventing mutations in the newly synthesized SARS-CoV-2 RNA.