indication

For the treatment of HIV infection and chronic hepatitis B (HBV).

pharmacology

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.

biotransformation

The only detected metabolite of lamivudine is trans-sulfoxide.

absorption

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.

half life

5 to 7 hours

route of elimination

The primary routes of elimination of abacavir are metabolism by alcohol dehydrogenase to form the 5′-carboxylic acid and glucuronyl transferase to form the 5′-glucuronide. Lamivudine is excreted in human breast milk and into the milk of lactating rats.

drug interactions

Tobramycin: Increased risk of nephrotoxicity

Valganciclovir: The adverse/toxic effects of reverse transcriptase inhibitors (nucleoside), such as Lamivudine, may be enhanced by Valganciclovir. There is a risk of hematologic toxicity. Diligent monitoring during concomitant therapy is recommended.

Zalcitabine: Lamivudine may reduce the efficacy of zalcitabine. Combination therapy is not recommended.