A 62-year-old woman with severe post-operative pain following abdominal hysterectomy is on IV morphine 10 mg 4-hourly. Despite adequate analgesia, she develops respiratory depression (RR 8/min, SpO2 88%) and miosis. Which of the following is the MOST appropriate immediate management?

Explanation

## Opioid-Induced Respiratory Depression Management **Correct Answer: Naloxone IV bolus** The patient presents with classic signs of opioid toxicity: respiratory depression (RR 8/min, SpO2 88%) and miosis (pinpoint pupils). These are hallmark features of opioid overdose. ### Why Naloxone is Correct: - **Mechanism:** Naloxone is a competitive opioid antagonist that rapidly reverses opioid effects by displacing opioids from μ-receptors - **Dosing:** Initial dose 0.4 mg IV push; can repeat every 2–3 minutes up to 10 mg if needed - **Onset:** Works within 1–2 minutes IV - **Duration:** Short (30–90 min), so infusion may be needed if opioid half-life is longer - **Indication:** Immediate reversal of life-threatening respiratory depression is the priority ### Key Point: **Respiratory depression (RR <8) with hypoxemia is a medical emergency.** Supportive measures (oxygen, bag-mask ventilation) are concurrent but naloxone is the definitive antidote. ### Clinical Pearl: Post-operative opioid dosing must account for age, renal/hepatic function, and concurrent medications. This 62-year-old may have reduced clearance, leading to accumulation.