This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anatomy, Subject name: Anatomy
The basis of combining Ritonavir with Lopinavir 
Select and explain. 
A. Pharmaceutical compatability, B. CYP3A4 inhibiton NY Ritonavir, C. Long elimination half life of Ritonavir, D. Ability to counteract side effects of Lopinavir
B: CYP3A4 inhibiton NY Ritonavir
Answer: B: CYP3A4 inhibiton NY Ritonavir 
Explanation: Refer Katzung 10/e p810 Ritonavir is a microsomal enzyme inhibitor paicularly of CYP3A4 .it decreases the metabolism of other drugs and thus lower dose of Lopinavir can be used in treatment of HIV when combined with Ritonavir