Entecavir
Entecavir is a guanosine nucleoside analogue with selective activity against hepatitis B virus (HBV). It is designed to selectively inhibit the Hepatitis B virus, blocking all three steps in the replication process. Entecavir is more efficient than an older Hepatitis B drug, lamivudine. By competing with the natural substrate deoxyguanosine triphosphate, entecavir functionally inhibits all three activities of the HBV polymerase (reverse transcriptase, rt): (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. Absorption Following oral administration in healthy subjects, entecavir peak plasma concentrations occurred between 0.5 and 1.5 hours. In healthy subjects, the bioavailability of the tablet is 100% relative to the oral solution.
Primary Characteristics
It is of Synthetic origin.
It belongs to Antiviral Agents pharmacological group on the basis of mechanism of action.
Molecular Weight: 295.3 · pKa: 14.64 · Solubility in Water: Slightly soluble (2.4 mg/mL at pH 7.9, 25°C) · Non-proprietary name: Entecavir.
Pharmacokinetics
Absorption: Entecavir has an oral bioavailability is 1% (±0.5%).
Distribution: Entecavir has a plasma protein binding is 13%.
Elimination: it is metabolised via Hepatic, plasma half-life is 128-149hrs., renal excretion is 62-73%.
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Indications
Entecavir is primarily indicated in conditions like Chronic hepatitis B infection.
Contraindications
None recorded.
Dosage
Entecavir's dosage details are as follows:
| Dose | Single Dose | Frequency | Route | Instructions |
|---|---|---|---|---|
| Adult Dosage | ||||
| 1 – 1 mg | — | Every 24h | PO | For amivudin refrectory or known lamivudine or telbivodine resistance mutations. Decompensated liver disease |
| 0.5 – 0.5 mg | — | Every 24h | PO | Once daily |
| Paediatric Dosage (20kg) | ||||
| No data. | ||||
| Neonatal Dosage (3kg) | ||||
| No data. | ||||
Drug Interactions
None recorded.
Side Effects
Entecavir in overdosage may give rise to further complications which include Liver symptom.
Entecavir produces potentially life-threatening effects which include Lactic Acidosis , Lactic acidosis. Careful monitoring is needed with proper medical management.
Entecavir is known to cause more or less tolerable side effects which are usually transient. These include Cold legs, Difficulty breathing, dizziness, Fatigue, Headache, Irregular heart beat, Light headedness, Light-colored bowel movements, Loss of appetite, Muscle pain, Nausea, Stomachache , Tiredness , Vomiting , Weakness, Yellow discolortaion of skin and urine.