All of the following cause inhibition of CYP3A except:
Five protease inhibitors-Indinavir (IDV), Nelfinavir (NFV), Saquinavir (SQV), Ritonavir (V) and Lopinavir. 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,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. Ritonavir:It is a potent PI; also a potent CYP3A4 inhibitor. 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. ltraconazole: This newer orally active triazole antifungal has a broader spectrum of activity than KTZ or fluconazole;It is largely metabolized in liver by CYP3A4; an active metabolite is produced which is excreted in faeces ESSENTIALS OF MEDICAL PHARMACOLOGY K.D.TRIPATHI SIXTH EDITION PAGE NO:764,773
Saquinavir
Ritonavir
Itraconazole
Erythromycin
Chemotherapy