Drug Groups

approved; investigational

Description

A reverse transcriptase inhibitor and zalcitabine analog in which a sulfur atom replaces the 3' carbon of the pentose ring. It is used to treat Human Immunodeficiency Virus Type 1 (HIV-1) and hepatitis B (HBV).

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.

Affected Organisms

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

Protein Binding

36%

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.

Clearance

* Renal cl=280.4?+/-?75.2 mL/min [HIV-infected?patients given a single IV doses ranging from 0.25 to 8 mg/kg]

References

External Links