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Drugs reference index «Entecavir»


Pronunciation: (en-TEK-a-vir)Class: Antiviral Agent

Trade Names:Baraclude- Tablets 0.5 mg- Tablets 1 mg- Solution, oral 0.05 mg/mL


Inhibits hepatitis B virus (HBV) polymerase (reverse transcriptase) by competing with the natural substrate deoxyguanosine triphosphate.



Bioavailability of tablet is 100% relative to oral solution. T max is between 0.5 and 1.5 h. Steady state achieved after 6 to 10 days. For 0.5 mg dose, C max was 4.2 ng/mL and C trough was 0.3 ng/mL; for 1 mg dose, C max was 8.2 ng/mL and C trough was 0.5 ng/mL. Administration with food decreases C max by 44% to 46% and AUC by 18% to 20%.


Approximately 13% protein bound. Vd is in excess of total body water, suggesting extensive distribution into tissues.


No oxidative or acetylated metabolites found. Minor amounts of phase 2 metabolites (glucuronide, sulfate conjugates) noted.


Terminal elimination half-life is 128 to 149 h; accumulation half-life approximately 24 h. Eliminated predominantly by kidney (both glomerular filtration and tubular secretion), with 62% to 73% of dose recovered in the urine.

Special Populations

Renal Function Impairment

C max and AUC increased in patients with moderate to severe renal function impairment or with end-stage renal disease. Dose reduction recommended for patients with CrCl less than 50 mL/min.

Hepatic Function Impairment

Pharmacokinetics similar between hepatically impaired patients and healthy patients.


AUC was 29.3% greater in elderly subjects; most likely due to differences in renal function. Base dose adjustment of entecavir on renal function of patient and not on age.


Pharmacokinetic studies have not been conducted.

Indications and Usage

Treatment of chronic HBV in adults with evidence of active viral replication and either evidence of persistent elevations in serum aminotransferases (ALT or AST) or histologically active disease.


Standard considerations.

Dosage and Administration

Coadministration With Lamivudine or Lamivudine- or Telbivudine-Resistant PatientsAdults and Children 16 yr of age and older

PO 1 mg daily.

Nucleoside Treatment–Naive PatientsAdults and Children 16 yr of age and older

PO 0.5 mg daily.

Renal ImpairmentAdults and Children 16 yr of age and older


For CrCl 30 to 49 mL/min Nucleoside-naive patients

0.25 mg once daily or 0.5 mg every 48 h.

Lamivudine-refractory patients

0.5 mg once daily or 1 mg every 48 h.

For CrCl 10 to 29 mL/min Nucleoside-naive patients

0.15 mg once daily or 0.5 mg every 72 h.

Lamivudine-refractory patients

0.3 mg once daily or 1 mg every 72 h.

For CrCl less than 10 mL/min Hemodialysis or chronic peritoneal dialysis patients

If administered on a hemodialysis day, give entecavir after the hemodialysis session.

Nucleoside-naive patients

0.05 mg once daily or 0.5 mg every 7 days

Lamivudine-refractory patients

0.1 mg once daily or 1 mg every 7 days.

General Advice

  • Administer on an empty stomach, at least 2 h after a meal or 2 h before the next meal.
  • Oral solution and tablets may be used interchangeably on a mg-to-mg basis.
  • Oral solution contains entecavir 0.05 mg/mL. 10 mL of oral solution provides a 0.5 mg dose and 20 mL provides a 1 mg dose.
  • Oral solution is a ready-to-use product; dilution or mixing with water or any other liquid product is not recommended.
  • Oral solution is supplied with dosing spoon calibrated in 1 mL increments up to 10 mL. Hold spoon in vertical position and fill gradually to prescribed dose. Administer dose directly from dosing spoon. Rinse dosing spoon with water after each use.


Store at controlled room temperature (59° to 86°F). Protect oral solution from light.

Drug Interactions

Drugs that reduce renal function or compete for active tubular secretion

Serum concentrations of entecavir or the coadministered drug may be elevated, possibly increasing pharmacologic and adverse effects.

Laboratory Test Interactions

None well documented.

Adverse Reactions


Headache (4%); fatigue (3%).


Rash (postmarketing).


Diarrhea, dyspepsia (1%).


Exacerbation of hepatitis (12%).


Anaphylactoid reaction (postmarketing).

Lab Tests

Elevated ALT (12%); hematuria (9%); increased lipase (7%); glucosuria (4%); fasting hyperglycemia, increased total bilirubin (3%); increased creatinine (2%).



Coinfected with HIV and HBV

There is a potential for development of resistance to HIV nucleoside reverse transcriptase inhibitors if entecavir is used to treat chronic hepatitis B infection in patients with HIV infection that is not being treated with highly active antiretroviral therapy.


Acute exacerbations have occurred in patients who have discontinued antihepatitis B therapy, including entecavir. Monitor hepatic function closely with clinical and laboratory follow-up for at least several months in patients who discontinue antihepatitis B therapy. Resumption of antihepatitis B therapy may be warranted.

Lactic acidosis/hepatomegaly

Lactic acidosis and hepatomegaly with steatosis (including fatal cases) have been reported with use of nucleoside analogues alone or in combination with other antiretrovirals.


Monitor patients for evidence of lactic acidosis and hepatitis. Monitor closely for adverse reactions when entecavir is coadministered with drugs that are excreted renally or with drugs known to affect renal function (eg, cyclosporine). Monitor hepatic function for several months after discontinuing therapy. Monitor renal function carefully in liver transplant patients who have received or are receiving an immunosuppressant that may affect renal function (eg, cyclosporine, tacrolimus).


Category C .




Safety and efficacy in children younger than 16 yr of age not established.


Select dose with caution, reflecting greater frequency of decreased hepatic, renal, or cardiac function and comorbidity.

Renal Function

Dosage adjustments are recommended for patients with CrCl less than 50 mL/min, including patients on hemodialysis.



No experience reported.

Patient Information

  • Advise patient to review the patient information leaflet carefully before starting therapy and to read and check for new information each time the medication is refilled.
  • Review dosing schedule with patient.
  • Advise patient that each dose must be taken on an empty stomach, 2 h after a meal or 2 h before the next meal.
  • Advise patient or caregiver using oral solution to measure prescribed dose using supplied dosing spoon. Instruct patient or caregiver to hold spoon in upright position and gradually fill it to the mark corresponding to prescribed dose, and then to swallow medication directly from the spoon, rinse the spoon with water, and allow it to air dry. Caution patient or caregiver not to dilute or mix oral solution with any other liquid.
  • Advise patient that if a dose is missed to take it as soon as remembered on that day unless it is nearing time for the next dose, in which case, the dose should be skipped and the next dose taken at the scheduled time. Caution patient not to take more than 1 dose of entecavir in a day or to take 2 doses at the same time to catch up.
  • Caution patient not to change the dose or stop taking unless advised by health care provider. Advise patient that stopping therapy may result in severe exacerbation of the hepatitis.
  • Advise patient to get an HIV test before starting therapy and any time after that when there is a chance of exposure to HIV.
  • Advise patient that medication will not cure hepatitis B infection nor any other viral infection (eg, HIV) and to continue to take other antiviral medications as prescribed.
  • Advise patient that this therapy will not prevent transmission of hepatitis B to others and to avoid things that could spread hepatitis B to others: do not share needles or injection equipment; do not share personal items that have blood or body fluids on them (eg, toothbrushes, razor blades); do not have any kind of sex without protection (eg, condoms, dental dams).
  • Advise patient that it is not known if entecavir can prevent cirrhosis, liver failure, or liver cancer that may develop as a result of hepatitis B infection.
  • Instruct patient to immediately report any of the following to health care provider: appetite loss; bowel movements turn light in color; cold feeling, especially in arms and legs; difficulty breathing; dizziness; fast or irregular heart beat; generalized body discomfort; light-headedness; stomach pain with nausea and vomiting; unexplained drowsiness; unusual muscle pain; urine turns very dark in color; yellowing of the skin or eyes.

Copyright © 2009 Wolters Kluwer Health.

  • Entecavir MedFacts Consumer Leaflet (Wolters Kluwer)
  • Entecavir Detailed Consumer Information (PDR)
  • entecavir Advanced Consumer (Micromedex) - Includes Dosage Information
  • Baraclude Prescribing Information (FDA)
  • Baraclude Consumer Overview

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