The nurse admits a patient suspected of opioid overdose. Which of these findings is consistent with opioid overdose?

Choice A rationale Sinus tachycardia (a heart rate greater than 100 beats/min) is not a typical sign of opioid overdose. Opioids cause cardiovascular depression, usually leading to bradycardia (slowed heart rate) and hypotension. Tachycardia is more common in stimulant overdose (e.g., cocaine) or withdrawal. Choice B rationale Visual hallucinations are not a characteristic finding in pure opioid overdose. They are more commonly associated with hallucinogens, anticholinergics (e.g., atropine toxicity), or severe alcohol withdrawal (delirium tremens). Opioid overdose causes central nervous system depression, leading to reduced consciousness. Choice C rationale Pinpoint pupils (miosis) are a classic, common, and important sign of acute opioid intoxication due to the drug's stimulatory effect on the parasympathetic oculomotor nerve (cranial nerve III) nucleus. This finding, along with respiratory depression and decreased level of consciousness, forms the triad of opioid overdose. Choice D rationale Generalized itchiness (pruritus) is a common side effect of opioid administration (especially intravenous) due to peripheral histamine release, but it is not a core or distinguishing sign of a life-threatening acute overdose. The critical findings relate to severe CNS and respiratory depression.