GHB Intoxication — MRCPsych Paper B MCQ

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ModerateSubstance MisuseGHB IntoxicationMRCPsych Paper B

A 25-year-old man is brought to the emergency department 30 minutes after taking gamma-hydroxybutyrate (GHB) at a party. He has a Glasgow Coma Scale score of 10, snoring respirations at 8 breaths/min and oxygen saturation of 89% on air. Pulse is 52 beats/min, blood pressure 118/72 mmHg and tympanic temperature 35.8°C. Which complication requires immediate prioritisation?

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Correct answer: B — Respiratory depression with loss of airway protection

GHB is a CNS depressant acting at GABA-B and GHB receptors, and acute toxicity characteristically produces rapid-onset coma with reduced rate and depth of respiration, sometimes apnoea. Here the depressed GCS, snoring respirations at 8/min and hypoxaemia indicate hypoventilation with a threatened airway, so airway positioning, oxygen and ventilatory support are the immediate priorities, escalating to intubation if oxygenation or airway protection cannot be maintained. Treatment is supportive: neither flumazenil nor naloxone reliably reverses GHB. Aspiration is a real consequence of an unprotected airway but is not yet established here and is prevented by managing B. Bradycardia at 52/min with normal blood pressure is haemodynamically tolerated and typical of GHB. Seizures are described but no seizure activity is reported. A temperature of 35.8°C is mild and does not outrank airway compromise.

Reference: Electronic Medicines Compendium (emc). Sodium Oxybate 500 mg/ml Oral Solution — Summary of Product Characteristics, sections 4.4 and 4.9 (overdose). https://www.medicines.org.uk/emc/product/100171/smpc