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Beta-blocker Overdose — EECC MCQ

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HardCardiac PharmacologyBeta-blocker OverdoseEECC

A 35-year-old man is brought to the emergency department after intentionally ingesting 50 tablets of atenolol 100 mg. He is profoundly bradycardic (HR 30 bpm), hypotensive (BP 60/40 mmHg), and obtunded. Atropine 3 mg IV and glucagon 10 mg IV have been administered without response. What is the next most appropriate intervention?

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Correct answer: E — High-dose insulin euglycaemic therapy with dextrose

In severe beta-blocker overdose refractory to atropine and glucagon, high-dose insulin euglycaemic therapy (HIET) is the recommended next-line treatment. HIET works by enhancing myocardial carbohydrate utilisation, improving cardiac contractility and output independent of the beta-adrenergic pathway. Typical dosing is an insulin bolus (1 unit/kg) followed by an infusion (0.5-2 units/kg/hr) with 50% dextrose to maintain euglycaemia and potassium monitoring. IV lipid emulsion is primarily used for lipophilic drug toxicity (e.g. local anaesthetic toxicity, propranolol) and may be considered as adjunct. Isoprenaline may partially overcome beta-blockade but is often insufficient in massive overdose. Pacing addresses rate but not the myocardial depression.

Reference: NPIS/Toxbase Guidelines on Beta-blocker Overdose; AACT Position Statement: https://bnf.nice.org.uk/