Indication
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.
Pharmacology
Entecavir is a guanosine nucleoside analogue with potent and selective activity against HBV polymerase. For pharmacological action it is phosphorylated to the active triphosphate (TP) form. Entecavir triphosphate functionally inhibits all 3 activities of the viral polymerase-
Priming of the HBV polymerase,
Reverse transcription of the negative strand from the pregenomic messenger RNA
Synthesis of the positive strand HBV DNA.
Dosage
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).?ÿAdult 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.
Interaction
Since Entecavir is predominantly eliminated by the kidney, coadministration with drugs that reduce renal function or compete for active tubular secretion may increase serum concentrations of either drug.
Contradiction
Entecavir is contraindicated in patients with previously demonstrated hypersensitivity to Entecavir or any component of the product.
Side Effect
The most common side effects are headache, fatigue, dizziness and nausea.
Pregnancy
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.
Precaution
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.
Overdose
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.
Storage
Store at temperatures not above 30?øC.