Dosing & Uses
Dosage Forms & Strengths
tablet
- 0.5mg
- 1mg
oral solution
- 0.05mg/mL
Chronic Hepatitis B
Indicated for treatment of CHB with evidence of active viral replication and either evidence of persistent elevations in serum aminotransferases (ALT or AST) or histologically active disease
Nucleoside inhibitor treatment-naïve with compensated liver disease (adults and adolescents ≥16 yr): 0.5 mg PO qDay
Lamivudine-refractory or known lamivudine or telbivudine resistance substitutions (adults and adolescents ≥16 yr): 1 mg PO qDay
Decompensated liver disease (adults): 1 mg PO qDay
Indication is based on the following
- Histologic, virologic, biochemical, and serologic responses in nucleoside-treatment-naïve and lamivudine-resistance with HBeAg-positive or HBeAg-negative chronic HBV infection and compensated liver disease
- Virologic, biochemical, serologic, and safety data are available from a controlled study with chronic HBV infection and decompensated liver disease
- Virologic, biochemical, serologic, and safety data are available for a limited number of adults with HIV/HBV coinfection who have received prior lamivudine therapy
Renal Impairment
Usual daily dose (0.5 mg)
- CrCl ≥50 mL/min: No dosage adjustment required
- CrCl 30-49 mL/min: Reduce to 0.25 mg/day or 0.5 mg q48hr
- CrCl 10-29 mL/min: Reduce to 0.15 mg/day or 0.5 mg q72hr
- CrCl <10 mL/min, hemodialysis, or CAPD: 0.05 mg/day or 0.5 mg q7days
Lamivudine-refractory/decompensated liver disease daily dose (1 mg)
- CrCl ≥50 mL/min: No dosage adjustment required
- CrCl 30-49 mL/min: Reduce to 0.5 mg/day or 1 mg q48hr
- CrCl 10-29 mL/min: Reduce to 0.3 mg/day or 1 mg q72hr
- CrCl <10 mL/min, hemodialysis, or CAPD: 0.1 mg/day or 1 mg q7days
Administration
Take on empty stomach (2 hr AC or PC)
Use oral solution when needed for renal impairment dosage adjustments
Dosage Forms & Strengths
tablet
- 0.5mg
- 1mg
oral solution
- 0.05mg/mL
Chronic Hepatitis B
Indicated for treatment of CHB with evidence of active viral replication and either evidence of persistent elevations in serum aminotransferases (ALT or AST) or histologically active disease in children ≥2 years and weigh at least 10 kg
<2 years: Safety and efficacy not established
≥16 years: As adult
Nucleoside inhibitor treatment-naïve
- Administer PO once daily
- 10-11 kg: 0.15 mg (3 mL)
- >11-14 kg: 0.2 mg (4 mL)
- >14-17 kg: 0.25 mg (5 mL)
- >17-20 kg: 0.3 mg (6 mL)
- >20-23 kg: 0.35 mg (7 mL)
- >23-26 kg: 0.4 mg (8 mL)
- >26-30 kg: 0.45 mg (9 mL)
- >30 kg: 0.5 mg (10 mL oral solution or one 0.5-mg tab)
Lamivudine-experienced
- Administer PO once daily
- 10-11 kg: 0.3 mg (6 mL)
- >11-14 kg: 0.4 mg (8 mL)
- >14-17 kg: 0.5 mg (10 mL)
- >17-20 kg: 0.6 mg (12 mL)
- >20-23 kg: 0.7 mg (14 mL)
- >23-26 kg: 0.8 mg (16 mL)
- >26-30 kg: 0.9 mg (18 mL)
- >30 kg: 1 mg (20 mL oral solution or one 1-mg tab)
Renal Impairment
Insufficient data exist to recommend a specific dose adjustment in pediatric patients with renal impairment
Consider dose reductions or dosing interval increases similar to adult adjustments
Administration
Take on empty stomach (2 hr AC or PC)
Use oral solution for children weighing 10-30 kg
Adverse Effects
1-10%
Fatigue (1-3%)
Headache (2-4%)
Dizziness
Nausea
<1%
Diarrhea
Dyspepsia
Vomiting
Somnolence
Insomnia
Postmarketing Reports
Lactic acidosis
Increased transaminases
Warnings
Black Box Warnings
Severe acute exacerbations of hepatitis reported following discontinuing drug; monitor hepatic function
Resistance to HIV NRTIs may emerge in patients with chronic hepatitis B in whom HIV infection is unrecognized or untreated
Not for HIV/HBV coinfected patients unless being treated with highly active antiretroviral therapy (HAART)
Lactic acidosis and severe hepatomegaly with steatosis, including fatal cases, reported
Do not use Epivir HBV tablets or solution to treat HIV
Contraindications
Hypersensitivity
Cautions
Discontinuation may result in acute exacerbation of hepatitis B
Caution in liver transplant recipients or renal impairment
Pregnancy
Risk of HIV resistance: not recommended for HIV/HBV coinfected patients who are not also receiving HAART
Patients with decompensated liver disease may be at greater risk for lactic acidosis
Pregnancy & Lactation
Pregnancy
Pregnancy Registry: Healthcare providers are encouraged to register pregnant women exposed to entecavir by calling 1-800-258-4263.
Prospective pregnancy data from the APR are not sufficient to adequately assess the risk of birth defects, miscarriage or adverse maternal or fetal outcomes; use during pregnancy has been evaluated in a limited number of individuals reported to APR and number of exposures to entecavir is insufficient to make a risk assessment compared to a reference population; rate of miscarriage is not reported in APR; all pregnancies have a background risk of birth defect, loss, or other adverse outcomes
Animal data
- In animal reproduction studies, no adverse developmental effects were observed with entecavir at clinically relevant exposures; no developmental toxicities were observed at systemic exposures (AUC) approximately 25 (rats) and 200 (rabbits) times exposure at maximum recommended human dose (MRHD) of 1 mg/day
Lactation
Not known whether drug is present in human breast milk, affects human milk production, or has effects on the breastfed infant; when administered to lactating rats, entecavir was present in milk; developmental and health benefits of breastfeeding should be considered along with mother’s clinical need for therapy and any potential adverse effects on breastfed infant from drug or from underlying maternal condition
Pregnancy Registry: Healthcare providers are encouraged to register pregnant women exposed to entecavir by calling 1-800-258-4263.
Pregnancy Categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk. C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done. D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk. X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist. NA: Information not available.Pharmacology
Mechanism of Action
Selective HBV DNA polymerase inhibitor; inhibition blocks reverse transcriptase activity, which in turn reduces viral DNA synthesis
Pharmacokinetics
Half-Life, Elimination: 5-6 days
Peak Plasma Time: 0.5-1.5 hr
Peak Plasma Concentration: 0.5 mg dose: 4.2 ng/mL; 1 mg dose: 8.2 ng/mL
Distribution: Extensively in tissues
Protein Bound: 13%
Metabolism: Not a substrate, inducer or inhibitor of the Cytochrome P450 system
Excretion: Primarily urine
Images
Patient Handout
Formulary
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