A nurse is caring for a client who has been brought to the emergency department and is experiencing acute fentanyl toxicity. The nurse should expect to observe which of the following adverse effects in this client?

Rationale: A. Fentanyl and other opioids usually cause hypotension, not hypertension. CNS depression leads to vasodilation and reduced cardiac output. Hypertension is uncommon and not a primary sign of opioid overdose. B. Acute fentanyl toxicity causes miosis (pinpoint pupils) due to parasympathetic stimulation of the oculomotor nerve. Pinpoint pupils are a hallmark sign of opioid overdose and help differentiate opioid toxicity from stimulant overdoses, which cause dilated pupils. Recognizing this sign is critical for early identification and intervention. C. Opioid overdose results in respiratory depression, characterized by slow, shallow breathing or apnea, not increased respiratory rate. Respiratory depression is the most life-threatening effect of opioid toxicity. D. Opioid toxicity generally causes bradycardia, due to decreased sympathetic tone. Tachycardia is more characteristic of stimulant overdose or conditions causing sympathetic stimulation.