Name a common side effect of sedation.

Drowsiness or grogginess is a well-documented side effect of sedation. Sedation is intentionally used to reduce anxiety and discomfort during medical or dental procedures, but it can also lead to an altered state of consciousness that often results in the patient feeling sleepy or lethargic. This symptom is particularly common as the sedative agents work on the central nervous system, decreasing arousal and promoting calmness, which can lead to reduced physical and mental activity.

While increased alertness and a sudden burst of energy are not typical effects of sedation, nausea and vomiting can occur with some sedatives, but they are less directly associated with the expected sedative outcomes. Drowsiness, however, is a primary and expected effect, making it the most fitting answer in the context of common side effects of sedation.