Ritonavir inhibits metabolism of all of the following drugs except:
(A) Amiodarone (B) Phenytoin (C) Cisapride (D) Midazolam
(B) Ans. b. Phenytoin (Ref Goodman Gillman Ilth/1302; Katzung II/e plI44)Ritonavir inhibits metabolism of Amiodarone, Cisaprlde, Midazolam and but not the phenytoin'The majority (95%o) of phenytoin is metabolized principalty in the hepatic endoplasmic reticulum by CYP2C9/10 and to a lesser extent CYP2C9.'