Used in the treatment of HIV-1 infection as a protease inhibitor. It works by blocking the action of the HIV protease enzyme, preventing the virus from maturing and producing infectious particles. Atazanavir sulfate is typically administered in combination with other antiretroviral agents as part of highly active antiretroviral therapy (HAART). It is preferred in some patients due to a favorable lipid profile, causing less elevation in cholesterol and triglycerides compared to other protease inhibitors. Often boosted with low-dose ritonavir or cobicistat to enhance its plasma concentration and effectiveness. Not used as a standalone treatment but plays a key role in long-term management of HIV, helping reduce viral load and improve immune function.