Atazanavir sulfate is primarily used as an antiretroviral medication in the treatment of HIV-1 infection. It works by inhibiting the protease enzyme, which is essential for the replication of the virus. This helps to reduce the viral load in the body and improves immune system function. It is often prescribed as part of a combination therapy with other antiretroviral drugs to enhance its effectiveness and prevent the development of drug resistance. The medication is particularly valued for its once-daily dosing convenience, which improves patient adherence to the treatment regimen. Additionally, atazanavir sulfate is known to have a favorable lipid profile, making it a preferred option for patients at risk of cardiovascular complications. It is also used in certain cases to prevent mother-to-child transmission of HIV during pregnancy.