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Opioid Overdose Naloxone — FRCA Final MCQ

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ModerateTrauma & Emergency AnaesthesiaOpioid Overdose NaloxoneFRCA Final

A 30-year-old man is brought to the emergency department with a suspected opioid overdose. He has a GCS of 5, a spontaneous respiratory rate of 4 breaths per minute, pinpoint pupils and an SpO2 of 72% on air. Bag-mask ventilation with 100% oxygen has been commenced and intravenous access obtained. According to the UK high-dose intravenous naloxone regimen for life-threatening opioid toxicity, what initial dose should be given?

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Correct answer: E0.4 mg IV

The correct answer is E: 0.4 mg IV. A respiratory rate of 4 and SpO2 of 72% on air indicate peri-arrest, life-threatening opioid toxicity, for which the UK high-dose regimen starts with 400 micrograms IV while airway support and ventilation continue. The therapeutic aim is adequate ventilation and airway protection, not necessarily complete restoration of consciousness. A 0.1 mg titrated regimen is appropriate for less immediately life-threatening respiratory depression or when controlled reversal is important, such as postoperative, palliative-care or opioid-dependent patients. Doses of 2 mg and 4 mg are later escalation doses if initial treatment fails. Ten milligrams is not an initial dose; failure to respond after a large cumulative dose should prompt reconsideration of the diagnosis. Recurrent toxicity may require repeated boluses or an infusion because naloxone can wear off before the causative opioid.

Reference: Royal Cornwall Hospitals NHS Trust. Use of Naloxone in Suspected Opiate Overdose in Adults Clinical Guideline V4.0, Figure 1, 2026. https://doclibrary-rcht.cornwall.nhs.uk/DocumentsLibrary/RoyalCornwallHospitalsTrust/Clinical/Pharmacy/UseOfNaloxoneInSuspectedOpiateOverdoseInAdultsClinicalGuideline.pdf