Entecavir is a guanosine nucleoside analogue with potent and selective activity against HBV polymerase. For pharmacological action it is phosphorylated to the active triphosphate (TP) form. Entecavir triphosphate functionally inhibits all 3 activities of the viral polymerase-
- Priming of the HBV polymerase,
- Reverse transcription of the negative strand from the pregenomic messenger RNA
- Synthesis of the positive strand HBV DNA.
Dosage & Administration
Administration of Entecavir with food decreases absorption and so it should be taken in an empty stomach (at least 2 hours before or 2 hours after meal).
Adult over 16 years, not previously treated with nucleoside analogues: 0.5 mg once daily.
Adult over 16 years with lamivudine or telbivudine resistant chronic hepatitis B: 1 mg once daily.
Pregnancy & Lactation
Use in pregnancy: There are no adequate and well-controlled studies in pregnant women. Entecavir should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
Use in lactation: It is not known whether Entecavir is excreted in human milk. Mothers should be instructed not to breast-feed if they are taking Entecavir.