Severe verapamil poisoning with cardiogenic shock — MRCEM SBA MCQ

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HardToxicology and environmental emergenciesSevere verapamil poisoning with cardiogenic shockMRCEM SBA

A 36-year-old woman presents four hours after taking an intentional overdose of modified-release verapamil. She is drowsy but maintaining her airway. Her heart rate is 42 beats/min, blood pressure is 74/40 mmHg and ECG shows second-degree atrioventricular block. Bedside echocardiography shows severely reduced global left ventricular systolic function. Her blood pressure remains low after intravenous crystalloid, atropine and intravenous calcium; a noradrenaline infusion has been started. Capillary glucose is 18 mmol/L and serum potassium is 4.1 mmol/L. Critical care is at the bedside. Which additional treatment should be started now?

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Correct answer: D — Start a high-dose insulin infusion under critical-care monitoring.

This is severe verapamil poisoning with both impaired atrioventricular conduction and marked myocardial dysfunction. Shock persists despite initial fluid, atropine and calcium treatment, while noradrenaline is providing circulatory support. **High-dose insulin therapy should be started promptly** to address the myocardial component, with frequent glucose and potassium measurements and glucose supplementation adjusted to results. The presenting hyperglycaemia does not justify withholding insulin or automatically giving an initial glucose bolus. Treatment requires a monitored emergency or critical-care setting. ([rightdecisions.scot.nhs.uk](https://www.rightdecisions.scot.nhs.uk/media/r3smwntk/glucagon-and-high-dose-insulin-for-treatment-of-beta-blocker-alcium-channel-blocker-overdose-adults-only.pdf?utm_source=openai)) **A:** Glucagon is a plausible adjunct in calcium-channel-blocker poisoning, but is not the best next treatment for the demonstrated severe myocardial dysfunction. **B:** The atrioventricular block makes pacing attractive; pacing may help unstable bradycardia when myocardial contractility is relatively preserved, but is unlikely to resolve shock driven substantially by poor contractility. **C:** Lipid emulsion is an escalation to consider in refractory shock, rather than ahead of high-dose insulin here. **E:** Modified-release tablets make bowel decontamination worth considering in a suitable stable patient, but it does not take priority over treatment of this patient's established shock. Ongoing toxicology and critical-care input is required. ([pubmed.ncbi.nlm.nih.gov](https://pubmed.ncbi.nlm.nih.gov/27749343/))

Reference: NHS Lanarkshire: Glucagon and High Dose Insulin for Treatment of Beta Blocker/Calcium Channel Blocker Overdose — Adults Only (Approved December 2025) — https://www.rightdecisions.scot.nhs.uk/media/r3smwntk/glucagon-and-high-dose-insulin-for-treatment-of-beta-blocker-alcium-channel-blocker-overdose-adults-only.pdf Experts Consensus Recommendations for the Management of Calcium Channel Blocker Poisoning in Adults (March 2017) — https://pubmed.ncbi.nlm.nih.gov/27749343/ High-dose insulin euglycaemic therapy for a severe calcium channel blocker overdose (2026) — https://casereports.bmj.com/content/19/3/e268547