Saquinavir is primarily used as an antiretroviral medication in the treatment of HIV infection. It belongs to the protease inhibitor class, which works by blocking the activity of HIV protease, an enzyme essential for the virus to replicate. By inhibiting this enzyme, saquinavir prevents the production of mature, infectious viral particles, thereby reducing the viral load in the body. It is often prescribed as part of combination therapy, known as highly active antiretroviral therapy (HAART), to enhance its effectiveness and minimize the risk of drug resistance. This helps improve immune function, slow disease progression, and reduce the likelihood of HIV-related complications. Saquinavir is typically administered in conjunction with other antiretroviral drugs to ensure a comprehensive approach to managing HIV infection.