entecavir monohydrate: clinical use

Prescribing considerations

• Initiate under a clinician experienced in chronic hepatitis B management.
• Establish prior nucleoside exposure and lamivudine resistance.
• Determine HIV status and ensure effective antiretroviral therapy in HIV/HBV co-infection.
• Assess renal function, liver compensation and factors increasing lactic acidosis risk.
• Reinforce measures to prevent HBV transmission.

Contraindications and cautions

• Hypersensitivity to entecavir or any excipient.
• The tablet contains lactose and is unsuitable for people with galactose intolerance, total lactase deficiency or glucose-galactose malabsorption.

Monitoring

• HBV DNA and biochemical response, including ALT.
• Renal function, particularly with impairment, transplantation or potentially nephrotoxic medicines.
• Evidence of hepatic decompensation or lactic acidosis in higher-risk patients.
• Hepatic function after discontinuation because severe hepatitis exacerbations can occur.
• Virological breakthrough and resistance, especially after lamivudine-refractory disease.

Clinical pharmacology

Entecavir is a guanosine nucleoside analogue phosphorylated intracellularly to entecavir triphosphate. It inhibits HBV polymerase priming, reverse transcription and positive-strand DNA synthesis. It is predominantly eliminated unchanged by glomerular filtration and tubular secretion and is not a CYP450 substrate, inhibitor or inducer.

Formulation and product differences

• The selected product is a film-coated oral tablet containing lactose.
• An oral solution may be available when tablets cannot provide an appropriate prescription adjustment or cannot be swallowed.
• Tablet and oral-solution formulations were bioequivalent in healthy-subject studies.

Tablet

Route: Oral

Strengths: 0.5 mg, 1 mg