Entecavir

Brand Names: Baraclude

Drug Class: Nucleoside Reverse Transcriptase Inhibitor (NRTI)

Overview

Entecavir is a nucleoside analogue antiviral medication used for the treatment of chronic hepatitis B virus (HBV) infection in adults and pediatric patients 2 years and older with evidence of active viral replication and liver disease. It works by inhibiting HBV polymerase, effectively suppressing viral replication. Treatment requires careful monitoring due to risks of hepatitis exacerbation upon discontinuation and potential for lactic acidosis.

Mechanism of Action

Entecavir is a guanosine nucleoside analogue that selectively inhibits hepatitis B virus (HBV) polymerase. It competes with the natural substrate deoxyguanosine triphosphate to inhibit all three functions of HBV polymerase: (1) base priming, (2) reverse transcription of the negative strand from the pregenomic messenger RNA, and (3) synthesis of the positive strand of HBV DNA.

Indications

  • Treatment of chronic hepatitis B virus infection in adults and pediatric patients 2 years and older with evidence of active viral replication and either persistent elevations in serum aminotransferases (ALT/AST) or histologically active disease

Common Doses

  • 0.5 mg
  • 1 mg

Dosage

Typical dosage is 0.5 mg once daily for nucleoside-naïve patients and 1 mg once daily for lamivudine-refractory patients or those with decompensated liver disease. Should be administered on an empty stomach (at least 2 hours after a meal and 2 hours before the next meal).

Contraindications

  • None specifically listed in the label

Side Effects

  • Headache
  • Fatigue
  • Dizziness
  • Nausea
  • Diarrhea
  • ALT elevations (>10× ULN and >2× baseline in 2% of patients)
  • Peripheral edema (in decompensated patients)
  • Ascites (in decompensated patients)
  • Hepatic encephalopathy (in decompensated patients)

Interactions

  • Drugs that reduce renal function or compete for active tubular secretion may increase serum concentrations of entecavir or the coadministered drug
  • No significant interactions with lamivudine, adefovir, or tenofovir
  • Patients should be monitored closely when coadministered with renally eliminated drugs

Counseling Points

  • Take on an empty stomach (at least 2 hours after eating and 2 hours before next meal)
  • Do not stop taking without consulting your healthcare provider due to risk of severe hepatitis flare
  • Report any symptoms of lactic acidosis (weakness, muscle pain, trouble breathing, stomach pain with nausea/vomiting, cold feeling in arms/legs, dizziness, fast/irregular heartbeat)
  • Regular monitoring of liver function tests is required
  • Inform healthcare provider of all medications being taken