Used in the treatment of HIV infection, particularly in patients who cannot tolerate zidovudine. It works by inhibiting the reverse transcriptase enzyme, thereby preventing the virus from replicating. Due to its ability to cross the blood-brain barrier, it may help reduce viral load in the central nervous system. Mainly prescribed in combination with other antiretroviral drugs as part of a multidrug therapy regimen. Its use has declined over time due to the availability of newer agents with better safety profiles.