Used in the treatment of HIV-1 infection as part of antiretroviral therapy. It works by inhibiting the activity of reverse transcriptase, an enzyme that HIV needs to replicate its genetic material. By blocking this enzyme, the virus cannot multiply effectively, helping to reduce viral load and slow disease progression. Commonly prescribed in combination with other antiretroviral drugs to improve efficacy and reduce the risk of drug resistance. Often included in fixed-dose combination tablets for easier dosing. Mainly used in adults and children over a certain weight, typically in first-line treatment regimens.