Brands, Medical Use, Clinical Data
- Anti-HIV Agents
- Nucleoside and Nucleotide Reverse Transcriptase Inhibitors
Brands / Synonyms
3TC; Combivir; Epivir; Epivir-HBV; Epzicom; Hepitec; Heptovir; Lamivudine [Usan:Ban:Inn]; Trizivir; Zeffix
For the treatment of HIV infection and chronic hepatitis B (HBV).
Lamivudine is a nucleoside reverse transcriptase inhibitor (NRTI) with activity against Human Immunodeficiency Virus Type 1 (HIV-1) and hepatitis B (HBV). Lamivudine is phosphorylated to active metabolites that compete for incorporation into viral DNA. They inhibit the HIV reverse transcriptase enzyme competitively and act as a chain terminator of DNA synthesis. The lack of a 3'-OH group in the incorporated nucleoside analogue prevents the formation of the 5' to 3' phosphodiester linkage essential for DNA chain elongation, and therefore, the viral DNA growth is terminated.
Mechanism of Action
Lamivudine is a synthetic nucleoside analogue and is phosphorylated intracellularly to its active 5'-triphosphate metabolite, lamivudine triphosphate (L-TP). This nucleoside analogue is incorporated into viral DNA by HIV reverse transcriptase and HBV polymerase, resulting in DNA chain termination.
Lamivudine was rapidly absorbed after oral administration in HIV-infected patients. Absolute bioavailability in adults is 86% ± 16% for the tablet and 87% ± 13% for the oral solution.
Biotrnasformation / Drug Metabolism
The only detected metabolite of lamivudine is trans-sulfoxide.
EPIVIR Tablets and Oral Solution are contraindicated in patients with previously demonstrated
clinically significant hypersensitivity to any of the components of the products.
Lamivudine is predominantly eliminated in the urine by active organic cationic secretion. The possibility of
interactions with other drugs administered concurrently should be considered, particularly when their main route of
elimination is active renal secretion via the organic cationic transport system (e.g., trimethoprim).
TMP 160 mg/SMX 800 mg once daily has been shown to increase lamivudine exposure (AUC) by 44%. No change in dose of
either drug is recommended. There is no information regarding the effect on lamivudine pharmacokinetics of higher
doses of TMP/SMX such as those used to treat Pneumocystis carinii pneumonia. No data are available regarding
interactions with other drugs that have renal clearance mechanisms similar to that of lamivudine.
Lamivudine and zalcitabine may inhibit the intracellular phosphorylation of one another. Therefore, use of
lamivudine in combination with zalcitabine is not recommended.