Darunavir (trade name Prezista) is an orally active bis-furan-sulfonamide inhibitor of human immunodeficiency virus (HIV-1) protease. Darunavir was developed by Tibotec Pharmaceuticals (now Janssen R&D Ireland). Darunavir is indicated for the treatment of HIV-1 infection in adult and pediatric patients 3 years of age and older. The drug is co-administered with low-dose ritonavir and other anti-HIV agents. It is the only antiretroviral that has been registered at two different doses, 800/100 mg once-daily or 600/100 mg twice-daily, allowing its administration throughout the entire course of HIV disease, from naive subjects without any HIV-1 resistance to heavily treatment-experienced subjects with widespread triple-class family resistance.

Tipranavir (PNU-140690, trade mark APTIVUS) is a potent, orally bioavailable nonpeptidic HIV protease inhibitor of the 5,6-dihydro-4-hydroxy-2-pyrone sulfonamide class. Tipranavir has potent in vitro activity against a variety of HIV-1 laboratory strains and clinical isolates, including those resistant to ritonavir, as well as HIV-2. The drug is launched in several countries, including the US and in the EU. APTIVUS, co-administered with ritonavir, is indicated for combination antiretroviral treatment of HIV-1 infected patients who are treatment-experienced and infected with HIV-1 strains resistant to more than one protease inhibitor.

Atazanavir is the first once-daily protease inhibitor for the treatment of human immunodeficiency virus type 1 infection and should be used only in combination therapy, as part of a highly active antiretroviral therapy (HAART) regimen. In addition to being the most potent protease inhibitor in vitro, atazanavir has a distinct cross-resistance profile that does not confer resistance to other protease inhibitors. However, resistance to other protease inhibitors often confers clinically relevant resistance to atazanavir.

Nelfinavir is a protease inhibitor with activity against Human Immunodeficiency Virus Type 1 (HIV-1). Protease inhibitors block the part of HIV called protease. HIV-1 protease is an enzyme required for the proteolytic cleavage of the viral polyprotein precursors into the individual functional proteins found in infectious HIV-1. Nelfinavir binds to the protease active site and inhibits the activity of the enzyme. This inhibition prevents cleavage of the viral polyproteins resulting in the formation of immature non-infectious viral particles. Protease inhibitors are almost always used in combination with at least two other anti-HIV drugs. Nelfinavir inhibits the HIV viral proteinase enzyme which prevents cleavage of the gag-pol polyprotein, resulting in noninfectious, immature viral particles. Nelfinavir is used in combination with other antiviral drugs in the treatment of HIV in both adults and children. Nelfinavir is marketed under the brand name Viracept.

Amprenavir is an inhibitor of HIV-1 protease. Amprenavir binds to the active site of HIV-1 protease and thereby prevents the processing of viral gag and gag-pol polyprotein precursors, resulting in the formation of immature non-infectious viral particles. Amprenavir-containing combination regimens have shown virological efficacy, and have generally been well tolerated, in patients with HIV infection (primarily treatment-naive or protease inhibitor-naive). Fosamprenavir (GW433908, Lexiva, Telzir) is an oral prodrug of amprenavir, with a reduced daily pill burden. The use of protease inhibitors has also been associated with dyslipidemia and an increased risk of cardiovascular disease. Amprenavir activates Pregnane X receptor to mediate dyslipidemia.