What is a common symptom of respiratory depression in a patient?

Unresponsiveness is a common symptom of respiratory depression, which occurs when a person's breathing rate and depth are insufficient to maintain adequate oxygen levels in the blood. In respiratory depression, the brain does not receive enough oxygen, leading to a decreased level of consciousness. This may manifest as confusion, lethargy, or complete unresponsiveness as the body is not adequately able to sustain alertness.

Bradycardia, which refers to a slower than normal heart rate, may occur in some cases, but it is not a primary symptom directly associated with respiratory depression. Hyperactivity would be counterintuitive, as changes in consciousness often lead to reduced activity levels rather than increased. A severe headache could be a related symptom of hypoxia or increased intracranial pressure but is not specific to respiratory depression itself.

Thus, unresponsiveness aligns closely with the decreased respiratory drive and subsequent consequences on brain function.