All of the following cause inhibition of CYP3A except.
Saquinavir
Ritonavir
Itraconazole
Erythromycin
Ans. (A) Saquinavir(Ref: Katzung 11th/e p58, 863)All the drugs given in the options are microsomal enzyme inhibitors. Among protease inhibitors, ritonavir is the strongest inhibitor of CYP3A4 enzymes whereas saquinavir is the weakest.
Chemotherapy: General Principles