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Nucleoside analogue (HBV) Pregnancy: No adequate data in pregnant women; should not be used during pregnancy unless clearly necessary. Women of childbearing potential should use effective contraception. Breast-feeding should be discontinued during treatment.

Entecavir

Brand names: Baraclude

Entecavir is a nucleoside analogue antiviral used for the treatment of chronic hepatitis B virus infection in adults with active viral replication.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: 0.5 mg once daily (nucleoside-naive); 1 mg once daily (lamivudine-refractory or decompensated liver disease)
Route: Oral
Frequency: Once daily
For chronic hepatitis B; therapy initiated by a physician experienced in its management. Compensated liver disease, nucleoside-naive: 0.5 mg once daily with or without food. Lamivudine-refractory (viraemia on lamivudine or lamivudine-resistance mutations): 1 mg once daily on an empty stomach (>2 hours before and >2 hours after a meal); in the presence of LVDr mutations, combination with a second non-cross-resistant antiviral is preferred over monotherapy. Decompensated liver disease: 1 mg once daily on an empty stomach. Optimal duration unknown; treatment cessation not recommended in decompensated liver disease or cirrhosis. Paediatric: patients >=32.6 kg may take one 0.5 mg tablet (or 10 ml oral solution) daily with or without food; oral solution should be used below 32.6 kg.

Dose adjustments

Renal

Dose adjustment recommended for creatinine clearance <50 ml/min (including haemodialysis or CAPD). Nucleoside-naive: 0.25 mg once daily OR 0.5 mg every 48 h (CrCl 30-49); 0.15 mg once daily OR 0.5 mg every 72 h (CrCl 10-29); 0.05 mg once daily OR 0.5 mg every 5-7 days (<10/HD/CAPD). Lamivudine-refractory or decompensated: 0.5 mg once daily (CrCl 30-49); 0.3 mg once daily OR 0.5 mg every 48 h (CrCl 10-29); 0.1 mg once daily OR 0.5 mg every 72 h (<10/HD/CAPD). For doses <0.5 mg use oral solution; on haemodialysis days give after dialysis.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

  • Hypersensitivity to the active substance or to any of the excipients, or to soya oil

Side effects

  • Headache
  • Fatigue
  • Dizziness; somnolence; insomnia
  • Nausea, vomiting, diarrhoea, dyspepsia
  • Increased transaminases (exacerbations of hepatitis); rare lactic acidosis

Interactions

  • Drugs that reduce renal function or compete for active tubular secretion: may increase serum concentrations of entecavir or the co-administered drug; monitor closely
  • No significant interaction with lamivudine, adefovir dipivoxil or tenofovir disoproxil fumarate

Clinical monograph

How it works

Its active triphosphate inhibits hepatitis B virus polymerase (reverse transcriptase), suppressing viral DNA synthesis at the priming, reverse transcription and DNA-dependent synthesis steps.

Prescribing in practice

  • Discontinuation can cause severe acute exacerbations of hepatitis, so liver function must be monitored closely for a prolonged period after stopping.
  • It should not be used as the sole antiviral in patients with HIV co-infection that is untreated, owing to the risk of selecting HIV resistance.
  • Bioavailability is reduced by food, so it is taken on an empty stomach, and the dose is adjusted in renal impairment.

Monitoring

Monitor hepatic function and hepatitis B viral load during treatment and after discontinuation, along with renal function.

Counselling the patient

  • Take on an empty stomach, away from meals, to ensure proper absorption.
  • Do not stop the medicine abruptly without medical advice because hepatitis can flare.
  • Attend follow-up appointments and blood tests as scheduled.

Evidence & guidelines

Entecavir is recommended in NICE guidance for chronic hepatitis B and demonstrated potent viral suppression with a high genetic barrier to resistance in registration trials.

Reference: EASL HBV guidelines; NICE TA153/TA173; BHIVA hepatitis B guidelines; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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