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Antiviral — Hepatitis B (Nucleoside Analogue)

Entecavir

Brand names: Baraclude

Entecavir is an oral nucleoside analogue antiviral used as first-line treatment for chronic hepatitis B infection in adults.

Dosing — being independently re-sourced

ClinCalc Pro is rebuilding its dose data from primary open sources — the manufacturer SmPC (eMC), the WHO Model Formulary and other official references — under clinician review. This drug's structured dose is not yet published here. Confirm all doses against the product SmPC and your local formulary before prescribing.

Clinical monograph

How it works

It is phosphorylated intracellularly to its active triphosphate form, which competitively inhibits hepatitis B viral polymerase (reverse transcriptase), suppressing viral DNA replication.

Prescribing in practice

  • Severe acute exacerbation of hepatitis B can occur on stopping treatment, so discontinuation requires careful specialist supervision with monitoring of liver function for several months afterwards.
  • It has a high genetic barrier to resistance but is not recommended as monotherapy in patients with lamivudine-resistant hepatitis B, where resistance emerges readily.
  • The dose interval should be extended in renal impairment, and it should be taken on an empty stomach as food reduces absorption.

Monitoring

Monitor liver function and hepatitis B viral load during treatment, and continue clinical and biochemical monitoring after stopping because of the risk of post-treatment flare.

Counselling the patient

  • Take on an empty stomach, well away from food, and do not stop the medicine without advice from your specialist.
  • Report any worsening tiredness, jaundice or dark urine, especially after the medicine is stopped.

Evidence & guidelines

NICE recommends nucleos(t)ide analogues including entecavir for the treatment of chronic hepatitis B.

Reference: EASL Clinical Practice Guidelines HBV 2017; Chang et al. NEJM 2006 (entecavir phase III); Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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