True about protease inhibitors are all EXCEPT:
Retroviral protease Inhibitors (Pis) An aspaic protease enzyme encoded by HIV is involved in the production of structural proteins and enzymes (including reverse transcriptase) of the virus. The large viral polyprotein is broken into various functional components by this enzyme. This protease acts at a late step in HIV replication, i.e. maturation of the new virus paicles when the RNA genome acquires the core proteins and enzymes. Five protease inhibitors-Indinavir (IDV), Nelfinavir (NFV), Saquinavir (SQV), Ritonavir (V) and Lopinavir (in combination with ritonavir LPV /r) have been marketed in India for use against HIV. They bind to the protease molecule, interfere with its cleaving function, and are more effective viral inhibitors than AZT. Because they act at a late step of viral cycle, they are effective in both newly and chronically infected cells. Under their influence, HIV-infected cells produce immature noninfectious viral progeny-hence prevent fuher rounds of infection. Saquinavir: Two types of formulations (hard gel and soft gel capsules) with differing, but low oral bioavailability have been produced. The tablet load is large and side effects are frequent; photosensitivity can occur. It is a weak inhibitor of CYP3A4. ESSENTIALS OF MEDICAL PHARMACOLOGY K.D.TRIPATHI SIXTH EDITION PAGE NO:772
Acts as a substrate for P-glycoprotein (P-gp) and action is mediated by mdr-1 gene
Undergo hepatic oxidative metabolism
Protease inhibitors interfere with metabolism of several drugs
Saquinavir causes maximum induction of CYP3A4
Chemotherapy