Entecavir

Oral
Chronic hepatitis B

Nucleoside treatment-naive patients:

CrCl (mL/min)	Dosage
<10	0.05 mg once daily or 0.5 mg every 5-7 days.
10-29	0.15 mg once daily or 0.5 mg every 72 hours.
30-49	0.25 mg once daily or 0.5 mg every 48 hours.
≥50	0.5 mg once daily.

Lamivudine-refractory or decompensated liver disease patients:

CrCl (mL/min)	Dosage
<10	0.1 mg once daily or 0.5 mg every 72 hours.
10-29	0.3 mg once daily or 0.5 mg every 48 hours.
30-49	0.5 mg once daily.
≥50	1 mg once daily.

Patient on haemodialysis or CAPD: Nucleoside treatment-naive patients: 0.05 mg once daily or 0.5 mg every 5-7 days. Lamivudine-refractory or decompensated liver disease patients: 0.1 mg once daily or 0.5 mg every 72 hours. Dosage recommendations may vary among countries. Refer to country-specific product guidelines.

May be taken with or without food. For patients w/ compensated liver disease & nucleoside treatment-naïve, take w/ or w/o food.
Should be taken on an empty stomach. For patients w/ decompensated liver disease or w/ compensated liver disease who are lamivudine-refractory, take on an empty stomach more than 2 hr before or 2 hr after meals.

Hypersensitivity.

Patient with risk factors for liver disease (e.g. prolonged nucleoside inhibitor use, obesity, female gender); HIV co-infection. Liver transplant recipient. Not for use in HIV/hepatitis B virus co-infected patients not receiving HAART. Renal and hepatic impairment. Children. Pregnancy and lactation.

Significant: HIV resistance (patients with untreated HIV infection or without highly active antiretroviral therapy [HAART]).
Gastrointestinal disorders: Nausea, vomiting, diarrhoea, dyspepsia.
General disorders and administration site conditions: Fatigue.
Nervous system disorders: Headache, dizziness, somnolence.
Psychiatric disorders: Insomnia.
Skin and subcutaneous tissue disorders: Rash, alopecia.
Potentially Fatal: Lactic acidosis, severe hepatomegaly with steatosis; severe acute exacerbations of hepatitis B following treatment discontinuation.

PO: C

Screen for HIV status prior therapy initiation. Monitor LFTs periodically during treatment and several months after discontinuation. Assess for signs and symptoms of lactic acidosis and hepatotoxicity.

Concomitant use with drugs that reduce renal function or compete for active tubular secretion may increase serum concentrations of either medicinal product.

Decreased absorption with food.

Description:
Mechanism of Action: Entecavir is a nucleoside reverse transcriptase inhibitor which competes with natural substrates to inhibit hepatitis B viral polymerase enzyme thereby blocking reverse transcriptase activity thus reducing viral DNA synthesis.
Pharmacokinetics:
Absorption: Rapidly absorbed from the gastrointestinal tract. Decreased absorption with food. Time to peak plasma concentration: 30-90 minutes.
Distribution: Extensively distributed. Plasma protein binding: Approx 13%.
Metabolism: Partially metabolised in the liver via glucuronide or sulfate conjugation.
Excretion: Mainly via urine (60-73% as unchanged drug). Terminal elimination half-life: Approx 128-149 hours.

Source: National Center for Biotechnology Information. PubChem Compound Summary for CID 135398508, Entecavir. https://pubchem.ncbi.nlm.nih.gov/compound/Entecavir. Accessed June 28, 2022.

Store below 30°C. Protect from light. Use appropriate personal protective equipment (e.g. gloves) for receiving, handling, administration, and disposal. Storage instructions may vary among countries. Refer to specific product guidelines.

Antivirals

J05AF10 - entecavir ; Belongs to the class of nucleoside and nucleotide reverse transcriptase inhibitors. Used in the systemic treatment of viral infections.

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Baraclude 0.05 mg/mL Oral Solution (Bristol-Myers Squibb Pharma EEIG). MHRA. https://products.mhra.gov.uk. Accessed 05/05/2022.

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Buckingham R (ed). Entecavir. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 05/05/2022.

Joint Formulary Committee. Entecavir. British National Formulary [online]. London. BMJ Group and Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 05/05/2022.

Novartis New Zealand Limited. Entecavir 0.5 mg and 1 mg Film-coated Tablet data sheet 03 December 2020. Medsafe. http://www.medsafe.govt.nz. Accessed 20/06/2022.