Protease inhibitors interfere with the production of new viruses. This is achieved by inhibiting the enzyme, protease, which is involved in the production of new viruses. Without this enzyme, the virus cannot reproduce.

Protease inhibitors include:

• Amprenavir (Agenerase)
• Indinavir (Crixivan)
• Nelfinavir (Virac)
• Ritonavir (Norvir)
• Saquinavir (Invirase, Fortovase)
• Atazanavir (Reyataz)
• Tenofovir disoproxil (Viread)

Drugs that combine two protease inhibitors include:

• Lopinavir and ritonavir (Kaletra)

Drugs that combine a nucleotide reverse transcriptase inhibitor and a protease inhibitor include:

• Emtricitabine and tenofovir disoproxil (Truvada)