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Beta-blocker and calcium-channel-blocker poisoning
Beta-blocker and calcium-channel-blocker poisoning cause bradycardia, hypotension and shock; treatment is stepwise — atropine, fluids, calcium, high-dose insulin with glucose and vasopressors — and glucagon is mainly for beta-blockers.
Why it matters in the exam
The classic question shows a patient with a pulse of 40 and low blood pressure after swallowing tablets, and asks for the next step after atropine and fluids have failed. The correct answer includes IV calcium, high-dose insulin with glucose (HIET) and noradrenaline or adrenaline, and in beta-blocker poisoning also glucagon.
A diagnostic clue that is asked is the glucose level: calcium-channel-blocker poisoning tends to cause hyperglycaemia (blocked insulin release), which signals severity, while beta-blockers — especially in children — may cause low glucose. Differences between the drugs are also asked: propranolol widens the QRS and causes seizures, sotalol prolongs the QT, and dihydropyridines (amlodipine) mainly cause vasodilation with an initial tachycardia.
Remember the observation period as well: sustained-release preparations, such as extended-release verapamil, can cause late deterioration many hours later, so a patient who swallowed them stays monitored for at least 24 hours even if well, and charcoal and whole bowel irrigation are considered. In cases resistant to all treatment, temporary pacing, lipid emulsion and extracorporeal support (ECMO) in a suitable centre are considered.
Key points
- Bradycardia and hypotension after an ingestion — think of beta-blockers or CCBs.
- Atropine and fluids, then calcium and glucagon.
- Refractory shock — insulin 1 unit/kg bolus and 1 unit/kg per hour with glucose, plus noradrenaline.
- Hyperglycaemia points to CCBs and signals severity.
- Sustained release — at least 24 hours of observation.
Summary table
| Treatment | Usual dose | When | Note |
|---|---|---|---|
| Atropine | 0.5–1 mg IV, may repeat | Symptomatic bradycardia | Usually only a partial effect |
| Calcium | Gluconate 10% 30 mL or chloride 10% 10 mL IV | CCB poisoning with hypotension | May repeat; chloride preferably through a central line |
| Glucagon | 5 mg IV bolus then an infusion | Mainly beta-blockers | Vomiting is common |
| High-dose insulin (HIET) | 1 unit/kg bolus then 1 unit/kg per hour | Refractory shock | Close glucose and potassium monitoring |
| Vasopressors | Noradrenaline or adrenaline infusion | Together with HIET | Titrate to MAP |
| Rescue | Pacing, lipid emulsion, ECMO | Resistance to all treatment | In a suitable centre |
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Sources
- Goldfrank's Toxicologic Emergencies, 11th edition (2019) — Beta-adrenergic antagonists; Calcium channel blockers
- Experts consensus recommendations for the management of calcium channel blocker poisoning in adults (Critical Care Medicine), 2017 — First-line and refractory treatment
- Tintinalli's Emergency Medicine: A Comprehensive Study Guide, 9th edition (2020) — Beta-blockers; Calcium channel blockers
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.