Protease inhibitors

Saquinavir, ritonavir and indinavir are well-known protease inhibitors in the treatment of HIV-infection. These drugs inhibit the enzymes (proteases) that split viral proteins. In this way the formation of essential polypeptides and enzymes is decreased. This leads to production of immature and non-functional new viruses, which are not able to infect new cells.

All protease inhibitors cause gastrointestinal side effects. Moreover, long-term therapy can be implicated in lipodystrophy and dyslipidemia. All protease inhibitors are inhibitors of the CYP3A4 system and thus interact with numerous other drugs.

1

Saquinavir inhibits HIV replication by blocking uncoating of the virus during penetration.

2

Combination of protease inhibitors and NRTI drugs produces additive antiviral effects and reduces the incidence of resistance. 

3

Indinavir is an irreversible inhibitor of the HIV protease.