Toxicology & Substance Use · Topic 7 of 17

Beta-Blocker & Calcium Channel Blocker Overdose

Toxicology · cardiovascular drug overdose

Beta-Blocker & Calcium Channel Blocker Overdose

Bradycardia and shock after a beta-blocker or CCB overdose: start vasopressors and high-dose insulin (1 U/kg), plus IV calcium for CCBs and glucagon for beta-blockers.

Key numbers

Give IV calcium for CCB poisoningCaCl₂ 1–2 g IV

High-dose insulin 1 U/kg, then 1 U/kg/h1 U/kg → 1 U/kg/h

Glucagon bolus, then infusion, for beta-blockersglucagon 2–10 mg IV

01 · GiveVasopressors for shock: norepinephrine or epinephrine

Start vasopressors for hypotension from either drug (AHA class 1): norepinephrine for vasodilatory shock, epinephrine or dobutamine for cardiogenic shock; avoid dopamine, and vasopressin as the only vasoactive agent.

02 · GiveHigh-dose insulin 1 U/kg, then 1 U/kg/h

Start high-dose insulin euglycemia therapy: regular insulin 1 U/kg IV bolus, then 1 U/kg/h, titrated up to 10 U/kg/h for refractory myocardial dysfunction, with dextrose to keep euglycemia.

03 · GiveGive IV calcium for CCB poisoning

For CCB poisoning give IV calcium: 10% calcium chloride 10–20 mL (1–2 g), preferably central, or 10% calcium gluconate 30–60 mL (3–6 g), every 10–20 minutes or as an infusion.

Presentation

What you'll see

Bradycardia, hypotension and cardiogenic shock must knowBoth overdoses cause bradycardia, AV block, hypotension, low systemic vascular resistance and cardiogenic shock; beta-blockers add hypoglycemia, seizures and altered mental status.

CCB hyperglycemia tracks severityCCBs block pancreatic L-type channels and cause insulin resistance, so hyperglycemia follows; a rising glucose predicts severe verapamil or diltiazem poisoning better than vital signs. Beta-blockers can cause hypoglycemia.

Diagnosis & monitoring

Work-up

Check glucose and potassium often on insulinDuring high-dose insulin check glucose every 20 minutes for the first hour then hourly, and potassium hourly while titrating; hypoglycemia and hypokalemia are the common adverse effects. Onset takes 15–45 minutes.

Do right now

In this order

First moves

Give IV calcium for CCB poisoningCaCl₂ 1–2 g IV

→

Glucagon bolus, then infusion, for beta-blockersglucagon 2–10 mg IV

→

Vasopressors for shock: norepinephrine or epinephrine

→

High-dose insulin 1 U/kg, then 1 U/kg/h1 U/kg → 1 U/kg/h

→

VA-ECMO for refractory cardiogenic shock

Why each step

Give IV calcium for CCB poisoningFor CCB poisoning give IV calcium: 10% calcium chloride 10–20 mL (1–2 g), preferably central, or 10% calcium gluconate 30–60 mL (3–6 g), every 10–20 minutes or as an infusion.

Glucagon bolus, then infusion, for beta-blockersFor beta-blocker bradycardia or hypotension give glucagon 2–10 mg IV, then 1–15 mg/h; it raises cAMP without beta receptors, but gains are modest, vomiting is common and tachyphylaxis occurs.

Vasopressors for shock: norepinephrine or epinephrineStart vasopressors for hypotension from either drug (AHA class 1): norepinephrine for vasodilatory shock, epinephrine or dobutamine for cardiogenic shock; avoid dopamine, and vasopressin as the only vasoactive agent.

High-dose insulin 1 U/kg, then 1 U/kg/hStart high-dose insulin euglycemia therapy: regular insulin 1 U/kg IV bolus, then 1 U/kg/h, titrated up to 10 U/kg/h for refractory myocardial dysfunction, with dextrose to keep euglycemia.

VA-ECMO for refractory cardiogenic shockRefer early for VA-ECMO in cardiogenic shock or arrest refractory to drugs; it was associated with improved survival. Try transcutaneous pacing for unstable bradycardia, though capture often fails.

Management

Orders

Atropine for bradycardia — often failsAtropine 0.5–1 mg IV every 3–5 minutes (up to 3 mg) is reasonable for symptomatic bradycardia, but in significant beta-blocker or CCB poisoning it often fails to restore perfusion.

Whole-bowel irrigation for sustained-release tabletsObserve asymptomatic patients and consider decontamination after a potentially toxic ingestion; for sustained-release preparations consider whole-bowel irrigation because toxicity can be delayed.

Give fluids while the patient is fluid-responsiveGive crystalloid (10–20 mL/kg boluses) only while the patient shows fluid responsiveness; these patients are often in cardiogenic shock and easily overloaded.

Red flags & don'ts

Avoid harm

Lipid emulsion is not recommended routinely avoidDo not give lipid emulsion routinely: AHA 2023 finds no benefit in beta-blocker poisoning and advises against routine use for CCBs; its role in periarrest after other therapies fail is uncertain.

Beta-blocker or calcium channel blocker?

Commonly confused

Glucose	Hypoglycemia possible
Classic first antidote	Glucagon
Both overdoses	Vasopressors, high-dose insulin, VA-ECMO if refractory
Drug-specific traps	Propranolol widens QRS; sotalol prolongs QT

More detail

Reference

Show 4 reference facts

Hemodialysis may be reasonable for life-threatening atenolol or sotalol poisoning, especially with kidney impairment, because these water-soluble drugs are dialyzable; no survival benefit is proven.

High-dose insulin acts as an inotrope by helping the myocardium use carbohydrate; CCB overdose itself blocks insulin secretion and causes insulin resistance.

Methylene blue has helped refractory vasodilatory shock mainly in case reports (often amlodipine); AHA 2023 calls its usefulness uncertain in CCB poisoning.

Evidence for every therapy is very low quality and treatments are usually given together; the consensus prioritizes them by the hemodynamic problem — bradycardia, poor contractility or vasodilation.

Pearl

Vasopressors and high-dose insulin carry the poisoned heart; calcium and glucagon are adjuncts, and VA-ECMO is the rescue.

Sources · Merck Manual Professional — Symptoms and Treatment of Specific Poisons (beta-blockers, calcium channel blockers) · St-Onge M et al. Experts consensus recommendations for the management of calcium channel blocker poisoning in adults. Crit Care Med 2017;45:e306–e315 · Rotella JA et al. Treatment for beta-blocker poisoning: a systematic review. Clin Toxicol 2020;58:943–983 (abstract confirmed via Europe PMC) · Woodward C et al. High dose insulin therapy, an evidence based approach to beta blocker/calcium channel blocker toxicity. DARU 2014;22:36 · Levine M et al. Assessment of hyperglycemia after calcium channel blocker overdoses involving diltiazem or verapamil. Crit Care Med 2007;35:2071–2075 (abstract confirmed via Europe PMC) · Lavonas EJ et al. 2023 AHA focused update on the management of patients with cardiac arrest or life-threatening toxicity due to poisoning. Circulation 2023;148:e149–e184 · Starter sheet built from the verified AGACNP fact map (facts reviewed 2026-10-15).