There are various viruses for which protease inhibitors have been developed (or are presently undergoing testing):
- HIV/AIDS: antiretroviral protease inhibitors (saquinavir, ritonavir, indinavir, nelfinavir etc.)
- Hepatitis C: experimental agents: BILN 2061, VX 950.
Given the specificity of the target of these drugs there is the risk, as in antibiotics, of the development of drug-resistant mutated viruses. To reduce this risk it is common to use together different drugs aimed at different targets.