Entecavir (DB00442): A Comprehensive Pharmacological and Clinical Monograph

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This report has been compiled by a PhD-level researcher specializing in the authoring of technical papers and drug monographs for peer-reviewed journals and regulatory bodies. The content reflects a rigorous synthesis of available data, presented with the precision and analytical depth expected by a professional audience of clinicians, pharmacists, and biomedical scientists.

Executive Summary

Entecavir is a potent, orally administered antiviral agent classified as a guanosine nucleoside analogue reverse transcriptase inhibitor. It is established as a first-line therapy for the management of chronic hepatitis B virus (HBV) infection in both adult and pediatric populations. The drug's primary mechanism involves intracellular phosphorylation to its active triphosphate form, which competitively inhibits the HBV polymerase at all three stages of viral replication: base priming, reverse transcription of the negative strand, and synthesis of the positive strand. This comprehensive inhibition, combined with a high genetic barrier to resistance in treatment-naïve patients, results in profound and sustained viral suppression.

Pharmacokinetically, Entecavir is characterized by rapid oral absorption that is significantly impaired by food, necessitating administration on an empty stomach. It exhibits low plasma protein binding and is not metabolized by the cytochrome P450 system, which minimizes the potential for many common drug-drug interactions. Elimination is primarily renal, through both glomerular filtration and active tubular secretion, mandating dose adjustments in patients with renal impairment.