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. Often prescribed in combination with other antiretroviral drugs to enhance effectiveness and reduce the risk of drug resistance. Mainly used in resource-limited settings or as an alternative therapy when first-line treatments are not suitable. Requires careful monitoring due to potential side effects like peripheral neuropathy and pancreatitis.