Which of the following is a potential side effect of α1-adrenergic blockade?

Alpha-1 adrenergic blockers primarily work by inhibiting the action of norepinephrine at alpha-1 receptors, which can lead to various physiological effects. One of the well-documented side effects of this class of medications is drowsiness and dizziness. This occurs due to the resultant vasodilation and lowering of blood pressure, which can lead to orthostatic hypotension. As a person stands up, the sudden drop in blood pressure can cause lightheadedness or dizziness. Additionally, these effects can induce a sense of sedation, contributing to drowsiness.

The rationale behind the other choices includes the fact that severe dry mouth is more commonly associated with medications that have anticholinergic properties rather than alpha-1 blockade. An increased heart rate may occur as a reflex response to hypotension but is not a direct side effect of alpha-1 blockade. Nausea and vomiting are not typically associated with alpha-1 adrenergic antagonism and are more often related to other classes of medications or conditions.