This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Kidney, Subject name: Pharmacology
The longest acting antihistaminic is 
Select and explain. 
A. Terfenadine, B. Astemizole, C. Fexofenadine, D. Cetrizine
A: Terfenadine
Answer: A: Terfenadine 
Explanation: Terfenadine is a prodrug broken down to fexofenadine.so long duration of action followed by astemizole Ref: Goodman Gillman 12th ed.Pg 924.