This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Other topics and Adverse effects, Subject name: Anatomy
Which antihypeensive is a prodrug and is coveed to its active form in brain? 
Select and explain. 
A. Clonidine, B. Methyldopa, C. Minoxidil, D. Nitroprusside
B: Methyldopa
Answer: B: Methyldopa 
Explanation: (Ref: KDT 6/e p547) Although both methyldopa and minoxidil are produrgs, conversion of methyldopa to a-methylnorepinephrine takes place in the brain whereas minoxidil is activated to minoxidil sulphate (by phase II reaction) in the periphery.