Vasodilators are commonly used in clinical practice, so make sure to get these facts straight.
Arteriolar Vasodilators: Calcium channel blockers, Potassium channel blockers, and Hydralazine. These cause reflex tachycardia and edema.
Venular dilators: Nitrates. These cause orthostatic hypotension.
Drugs that are Both Arteriolar and Venular dilators: all other vasodilators. These cause reflex tachycardia, edema, AND postural hypotension. A prime example would be alpha-1 blockers such as prazosin.
***There are 3 important dilators that act via increasing NO. These are Nitrates (venular), Hydralazine (arteriolar), and Nitroprusside (both).