Lamivir S indicated as part of antiretroviral combination therapy for the treatment of Human Immunodeficiency Virus (HIV) infected adults and children and also used in the treatment of Hepatitis B virus infection. Lamivir S is a synthetic nucleoside analogue and is phosphorylated intracellularly to its active 5′-triphosphate metabolite. This nucleoside analogue is incorporated into viral DNA by HIV reverse transcriptase and HBV polymerase, resulting in DNA chain termination.