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RT QTc — MRCPsych Paper B MCQ

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ModerateSchizophrenia & PsychosisRT QTcMRCPsych Paper B

A 32-year-old man with schizophrenia becomes severely agitated and violent on an inpatient psychiatric ward. Verbal de-escalation has failed, oral medication cannot be safely administered, and urgent rapid tranquillisation is required. An ECG recorded earlier today showed a prolonged QTc interval. There is no evidence of alcohol or opioid intoxication, respiratory compromise, or another contraindication to benzodiazepines. Which medication is most appropriate?

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Correct answer: D — Intramuscular lorazepam

The correct answer is D, intramuscular lorazepam. NICE recommends either IM lorazepam alone or IM haloperidol with IM promethazine for adult rapid tranquillisation, but specifically directs clinicians to avoid the haloperidol–promethazine combination when there is cardiovascular disease, including a prolonged QT interval, and to use IM lorazepam instead. Haloperidol, particularly intravenously, is inappropriate here because of its cardiac risk. IM olanzapine and IM aripiprazole are antipsychotic alternatives used in some protocols, but they are not the NICE-recommended choice when the decisive feature is prolonged QTc. After administration, consciousness, respiratory rate, pulse, blood pressure, temperature and hydration should be monitored in accordance with rapid-tranquillisation guidance.

Reference: National Institute for Health and Care Excellence. Violence and aggression: short-term management in mental health, health and community settings. NICE guideline NG10, recommendations 1.4.37–1.4.45, especially 1.4.39. 2015. https://www.nice.org.uk/guidance/ng10/chapter/Recommendations