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Calcium-channel blocker overdose — SCE Acute Medicine MCQ

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HardClinical pharmacology and poisoningCalcium-channel blocker overdoseSCE Acute Medicine

A 24-year-old man attends after taking an unknown number of modified-release verapamil tablets four hours ago. He is vomiting, drowsy and clammy. BP is 78/40 mmHg, pulse 42/min and ECG shows sinus bradycardia with a PR interval of 280 ms. Glucose is 13.8 mmol/L and lactate is 5.2 mmol/L. What is the most appropriate next step in management?

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Correct answer: C — Give intravenous calcium and discuss high-dose insulin euglycaemic therapy with poisons/critical care

This is severe calcium-channel blocker toxicity with shock, bradycardia, hyperglycaemia and lactic acidosis. Initial management includes IV calcium, early expert toxicology advice and high-dose insulin euglycaemic therapy in refractory shock. Atropine may be tried but is often insufficient, and sodium bicarbonate is more relevant for sodium-channel blockade such as tricyclic antidepressant poisoning.

Reference: TOXBASE; NPIS guidance