About Adefovir Antiretroviral Agent, Reverse Transcriptase Inhibitor (Nucleoside) Mechanism of Action of Adefovir Adefovir undergoes phosphorylation in the presence of cellular kinase enzyme to Adefovir diphosphate. This Adefovir diphosphate competitively inhibits HBV DNA polymerase and reverse transcriptase enzyme by competing with nucleoside adenosine triphosphate and inhibits DNA synthesis. Indications for Adefovir 1.Hepatitis B infection