A 48 year old man presents to the emergency room with severe headache and blurred vision. His blood pressure is 230/140. Ophthalmologic examination reveals blurred optic discs with indistinct margins. An intravenous drip of sodium nitroprusside is started.
What is the mechanism of action of this medication?
A- Alpha adrenergic antagonist
B- Beta adrenergic antagonist
C- Ganglion blocker
D- ACE inhibitor
E- Direct smooth muscle vasodilator
Sodium nitroprusside is a direct smooth muscle vasodilator. It works directly on the large arteries to lower systolic blood pressure.
The correct answer is E