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Anaphylaxis — ORE Part 1 MCQ

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EasyPharmacology & TherapeuticsAnaphylaxisORE Part 1

A 30-year-old woman develops widespread urticaria, facial swelling, wheeze and hypotension 5 minutes after intravenous midazolam sedation. What is the first-line drug treatment?

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Correct answer: DAdrenaline 500 micrograms IM

**A is correct.** The patient has anaphylaxis: rapid-onset urticaria and facial swelling with wheeze and hypotension following drug administration. In UK dental practice, immediate **IM adrenaline 500 micrograms** is first-line treatment; this is 0.5 mL of 1:1000 adrenaline solution. It treats airway oedema, bronchospasm and distributive shock. Chlorphenamine and hydrocortisone do not act quickly enough to reverse life-threatening airway or circulatory compromise and are not first-line. Nebulised salbutamol may be an adjunct for persistent bronchospasm but does not treat hypotension or upper-airway oedema. IV adrenaline 1 mg is inappropriate: IV adrenaline requires specialist experience and a dilute 1:10,000 preparation; undiluted 1:1000 must not be given intravenously.

Reference: Electronic Medicines Compendium. Adrenaline (Epinephrine) Injection (1:1000) for Anaphylaxis, SmPC, section 4.2, updated 11 February 2020. https://www.medicines.org.uk/emc/product/3449/smpc