A nurse is collecting data from a client who has substance use disorder and reports recently taking opioids. Which of the following findings should the nurse identify as a manifestation of opioid intoxication?

A. Tachycardia: Opioid intoxication typically causes bradycardia rather than tachycardia due to central nervous system depression and increased parasympathetic activity. Elevated heart rate is more commonly associated with stimulant use or withdrawal states, not opioid intoxication. B. Mental alertness: Opioids depress the central nervous system, leading to drowsiness, sedation, or stupor. Mental alertness is not consistent with opioid intoxication; instead, clients often present with decreased responsiveness and impaired cognition. C. Hyperreflexia: Opioid intoxication generally causes decreased reflexes due to CNS depression. Hyperreflexia is more characteristic of stimulant intoxication or opioid withdrawal, not acute opioid toxicity. D. Pinpoint pupils: Miosis, or constricted pupils, is a classic sign of opioid intoxication. Opioids stimulate the parasympathetic system via the Edinger-Westphal nucleus, causing the pupils to constrict. This is a reliable clinical indicator of opioid effects and is used in assessment of intoxication.