This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Chemotherapy: General Principles, Subject name: Pharmacology
[{'content': 'All of the following cause inhibition of CYP3A except. \nSelect and explain. \nA. Saquinavir, B. Ritonavir, C. Itraconazole, D. Erythromycin', 'role': 'user'}, {'content': 'Answer: A \nExplanation: 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.', 'role': 'assistant'}]