Entecavir is indicated for the treatment of chronic hepatitis B virus infection in adults with compensated liver disease, evidence of viral replication and histologically documented active liver inflammation or fibrosis. It is also effective in decompensated cirrhosis.
Hepatic viral infections (Hepatitis B)
By competing with the natural substrate deoxyguanosine triphosphate, entecavir functionally inhibits all three activities of the HBV polymerase (reverse transcriptase, rt):
Base priming,
Reverse transcription of the negative strand from the pregenomic messenger RNA, and
Synthesis of the positive strand of HBV DNA. Upon activation by kinases, the drug can be incorporated into the DNA which has the ultimate effect of inhibiting the HBV polymerase activity.
Administration of Entecavir with food decreases absorption and so it should be taken in an empty stomach (at least 2 hours before or 2 hours after meal). Adult over 16 years, not previously treated with nucleoside analogues: 0.5 mg once daily. Adult over 16 years with lamivudine or telbivudine resistant chronic hepatitis B: 1 mg once daily.
Co-administration of Entecavir with Lamivudine or Adefovir dipivoxil did not result in significant drug interactions. The effects of co-administration of Entecavir with other drugs that are eliminated through renal or are known to affect renal function have not been evaluated and patients should be monitored closely for adverse events when coadministered with such drugs.
Entecavir is contraindicated in patients with previously demonstrated hypersensitivity to Entecavir or any component of the product. Monitor liver function tests every 3 months, and viral and serological markers for hepatitis B every 3-6 months. Discontinue if deterioration in liver function, hepatic steatosis, progressive hepatomegaly or unexplained lactic acidosis. Recurrent hepatitis may occur on discontinuation.
The most common side effects are headache, fatigue, dizziness and nausea.
Use in pregnancy: There are no adequate and well-controlled studies in pregnant women. Entecavir should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Use in lactation: It is not known whether Entecavir is excreted in human milk. Mothers should be instructed not to breast-feed if they are taking Entecavir.
There is no experience of Entecavir overdosage reported in patients. Healthy subjects who received up to 20 mg daily for up to 14 days and single doses up to 40 mg had no unexpected adverse events. If overdosage occurs, the patient must be monitored for evidence of toxicity and standard supportive treatment as necessary.
Keep in a dry place and store below 30°C. Protect from light and keep out of the reach of children.
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