Entecavir 0.5 mg Tablet is antiviral formulation which is prescribed the treatment of hepatitis B virus. Active compound present in this formulation has molecular formula C12H15N5O3 with a molar mass of 277.279 g/mol. It is a nucleoside analog which works by inhibiting reverse transcription and DNA replication in the virus. This tablet does not get metabolized in the body and is excreted via kidney after elimination half of 128 to 149 hours. Entecavir 0.5 mg Tablet is clinically tested on several parameters for ensuring good effectiveness and no serious side effects if used under prescription.