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Entecavir

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Entecavir, Baraclude

  • See Also
  1. Nucleoside Reverse Transcriptase Inhibitor
  2. Chronic Hepatitis B Infection
  • Indications
  1. Chronic Hepatitis B Infection
  • Contraindications
  1. Lamivudine resistant HBV
  • Mechanism
  1. Nucleoside Reverse Transcriptase Inhibitor (nRTI) with Antiviral activity against Hepatitis B virus (HBV)
  2. Entecavir is a prodrug, activated in vivo to a 5-triphosphate metabolite
    1. Synthetic guanosine Nucleoside analog (to 2-deoxyguanosine)
  3. Competes with the the natural substrate deoxyguanosine triphosphate (dGTP), incorporating into viral DNA
    1. Reverse transcriptase inhibitor (viral RNA-dependent HBV DNA Polymerase)
  • Precautions
  1. Risk of severe HBV exacerbation on discontinuation
    1. Monitor for at least 2 months after discontinuation
  2. Risk of induced HIV resistance in undiagnosed HIV coinfection
    1. HIV Test before use
    2. Do NOT use in monotherapy in HBV/HIV infected patients
  • Medications
  1. Tablets: 0.5 mg
  2. Oral Solution: 0.05 mg/ml
  • Dosing
  • Chronic HBV
  1. General
    1. Take on an empty Stomach, separated at least 2 hours from mealtime (before or after)
    2. Reduce dose in eGFR <50 ml/min
      1. Dose after Hemodialysis
    3. Dosing assumes treatment naive patients
      1. Avoid in Lamivudine resistant HBV (previously treated with higher dose regimens)
  2. Adult (and child age >=16 years or weight >30 kg)
    1. Entecavir 0.5 mg once daily
  3. Child (age 2 years and older)
    1. Weight 10 to 11 kg: GIve 3 ml (0.15 mg) orally daily
    2. Weight 11 to 14 kg: GIve 4 ml (0.2 mg) orally daily
    3. Weight 14 to 17 kg: GIve 5 ml (0.25 mg) orally daily
    4. Weight 17 to 20 kg: GIve 6 ml (0.30 mg) orally daily
    5. Weight 20 to 23 kg: GIve 7 ml (0.35 mg) orally daily
    6. Weight 23 to 26 kg: GIve 8 ml (0.40 mg) orally daily
    7. Weight 26 to 30 kg: GIve 9 ml (0.45 mg) orally daily
    8. Weight >30 kg: GIve 10 ml (0.5 mg) orally daily (adult dosing)
  • Efficacy
  1. More effective than Lamivudine or Adefovir in HBV DNA level suppression
  • Adverse Effects
  1. Well tolerated overall
  2. Headache
  3. Fatigue
  4. Dizziness
  5. Nausea
  6. Rash
  7. Fever
  8. Lactic Acidosis
  9. Hepatic Steatosis
  • Safety
  1. Pregnancy Category C, but overall unknown safety (pregnancy exposure registry exists)
  2. Unknown safety in Lactation
  • Pharmacokinetics
  1. Elimination Half-Life: 128 to 149 hours
  • Resources
  1. Entecavir (DailyMed)
    1. https://dailymed.nlm.nih.gov/dailymed/lookup.cfm?setid=046e61c9-9298-4b2e-b76e-b26b81fecd20
  • References
  1. Hamilton (2020) Tarascon Pocket Pharmacopoeia
  2. (2013) Med Lett Drugs Ther 11(127): 19-30 [PubMed]