What is "protease inhibitor"

n. (context pharmacology virology English) A class of drugs used to treat or prevent infection by viruses such as HIV and hepatitis C.

n. an antiviral drug used against HIV; interrupts HIV replication by binding and blocking HIV protease; often used in combination with other drugs [syn: PI]

Protease inhibitor can refer to:

• Protease inhibitor (pharmacology): a class of medication that inhibits viral protease
• Protease inhibitor (biology): molecules that inhibit proteases

In biology and biochemistry, protease inhibitors are molecules that inhibit the function of proteases. Many naturally occurring protease inhibitors are proteins.

In medicine, protease inhibitor is often used interchangeably with alpha 1-antitrypsin (A1AT, which is abbreviated PI for this reason). A1AT is indeed the protease inhibitor most often involved in disease, namely in alpha 1-antitrypsin deficiency.

Protease inhibitors (PIs) are a class of antiviral drugs that are widely used to treat HIV/AIDS and hepatitis caused by hepatitis C virus. Protease inhibitors prevent viral replication selectively binding to viral proteases (e.g. HIV-1 protease) and blocking proteolytic cleavage of protein precursors that are necessary for the production of infectious viral particles.

Protease inhibitors have been developed or are presently undergoing testing for treating various viruses:

• HIV/ AIDS: antiretroviral protease inhibitors ( saquinavir, ritonavir, indinavir, nelfinavir, amprenavir etc.)
• Hepatitis C: boceprevir, telaprevir, simeprevir

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 several different drugs together that are each aimed at different targets.