Entekor-0.5 Tablets Entekor-0.5 contains Entecavir, a cyclopentyl guanosine analogue with selective activity against Hepatitis B Virus (HBV). Intracellularly, entecavir is phosphorylated to its active triphosphate form, entecavir triphosphate. It functionally competes with the natural substrate deoxyguanosine triphosphate (dGTP) to inhibit HBV DNA polymerase across all three phases of viral replication: base priming, reverse transcription of the negative strand from pregenomic RNA, and synthesis of the positive strand HBV DNA. It is indicated for the treatment of chronic hepatitis B infection in adults and pediatric patients with evidence of active viral replication and liver inflammation or fibrosis.