## Opioid Overdose Management: Immediate Reversal **Key Point:** Naloxone is a competitive opioid antagonist and the gold-standard antidote for acute opioid overdose with respiratory depression. It must be given urgently when RR <8/min and SpO₂ <85%. ### Mechanism of Action Naloxone competitively blocks μ-opioid receptors in the CNS, rapidly reversing respiratory depression, sedation, and hypotension. Onset is 1–2 minutes IV; duration is 30–90 minutes (shorter than most opioids). ### Dosing & Titration Protocol - **Initial dose:** 0.4–0.8 mg IV bolus - **Repeat:** Every 2–3 minutes up to cumulative 10 mg if inadequate response - **Redosing:** May be needed q20–60 min as naloxone wears off before the opioid - **IM/IN routes:** Acceptable if IV access unavailable **High-Yield:** Naloxone has a shorter half-life (30–90 min) than most opioids (morphine ~3 hrs). Patients may re-enter overdose after naloxone wears off — continuous monitoring and repeat dosing or infusion may be needed. ### Why Naloxone Over Supportive Care Alone? Although oxygen and ventilation support are adjuncts, they do NOT address the underlying μ-receptor agonism. Naloxone reverses the cause, restoring spontaneous breathing within minutes. Waiting for spontaneous recovery risks prolonged hypoxia, aspiration, and death. **Clinical Pearl:** In opioid-dependent patients, naloxone precipitates acute withdrawal (anxiety, agitation, diaphoresis, tachycardia) but this is preferable to death. Warn the patient and manage withdrawal symptoms with supportive care and benzodiazepines if needed. ### Supportive Measures (Concurrent) - High-flow oxygen to maintain SpO₂ >90% - Airway positioning, suction if needed - IV access and fluid resuscitation - Monitor for recurrence and re-dose naloxone or start infusion (0.4 mg/hr) if opioid half-life is long [cite:KD Tripathi 8e Ch 33]
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