This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiovascular system, Subject name: Pharmacology
Which of the following antihypeensive cause sedation 
Select and explain. 
A. Clonidine, B. Hydralizine, C. Losaan, D. Amilodipine
A: Clonidine
Answer: A: Clonidine 
Explanation: Refer kDT 6/e p546 The classic centrally acting antihypeensives such as clonidine, guanfacine and alpha-methyl-DOPA ( its active metabolite alpha-methyl-noradrenaline) induce peripheral sympathoinhibition and a fall in blood pressure as a result of alpha2-adrenoceptor stimulation in the brain stem. These drugs have lost much of their clinical impoance because of their unourable side-effects (sedation, dry mouth, impotence), which are also mediated by alpha2-adrenoceptors, although in other anatomical regions