A group of volunteers are involved in a phase 1 clinical trial
of a new autonomic drug. When administered by intravenous
bolus, the blood pressure increases. When given orally for 1
week, the blood pressure decreases. Which of the following
standard agents does the new drug most resemble?
(A) Atropine
(B) Clonidine
(C) Phentolamine (an α blocker)
(D) Phenylephrine
(E) Propranolol (a β blocker)
(B) Clonidine
Clonidine is a centrally-acting alpha-2 adrenergic agonist that can decrease blood pressure when given orally for an extended period of time. It is known to have a sympatholytic effect, which is similar to the description of the new autonomic drug in the scenario.