Beta-Blocker and Calcium-Channel Overdose
Objective: Recognize beta-blocker and calcium-channel blocker overdose. Support perfusion. Atropine and pacing may fail. Do not invent calcium, glucagon, or insulin doses.
Why this matters
Beta blockers and calcium-channel blockers slow the heart and drop the blood pressure. In overdose they can do both at once. The usual bradycardia drugs may not work. Some calcium-channel blockers also raise the blood sugar. That is a clue, not a diagnosis.
Serious care can include calcium, glucagon, high-dose insulin, and vasopressors. Those belong in the hospital or on a written EMS card. An improvised dose is easy to harm someone with. Call early. Support the airway and the blood pressure with what you are authorized to give. This site does not publish those doses.
- Bradycardia plus shock plus these bottles is the picture. A single adult pill can matter in a toddler.
- Atropine may do nothing. Transcutaneous pacing may not capture. Neither fact means you skip the monitor or the airway.
- Do not mix high-dose insulin, glucagon, or calcium from memory. Poison center or medical control, plus the written card, own those amounts.
- Possible beta-blocker or calcium-channel overdose. Airway and a monitor now.
- Atropine did not change the rate. I am not adding doses from memory.
- I am calling medical control. I need the written card, not an insulin dose from memory.
Clinical sequence
- Airway, oxygen if hypoxic, and a full monitor with a 12-lead. Bag if they are not breathing. These patients can seize or vomit.
- Identify the drug if you can. Verapamil and diltiazem are non-dihydropyridine calcium-channel blockers. They classically slow the heart and lower the blood pressure. Amlodipine can present with shock and a fast heart rate. Beta blockers slow the heart and lower the blood pressure. They sometimes lower the glucose.
- Start the usual unstable-bradycardia pathway, and expect failure. Atropine and pacing may not work. Move to the overdose card. Do not repeat atropine until the patient arrests.
- Check glucose. A calcium-channel overdose can cause hyperglycemia. A beta-blocker overdose can cause hypoglycemia. Treat low glucose with your usual hypoglycemia pathway.
- If the protocol includes calcium, glucagon, or a vasopressor for this exact poisoning, use that written instruction and a second clinician to read it. Otherwise transport and call. Charcoal is only if your ingestion protocol says the airway is protected and the time window is open.
Teaching points
- AHA toxicologic guidance and poison-center practice put high-dose insulin and carefully titrated vasopressors in the hospital or in a protocol, not in a remembered drip.
- This is not the same as giving diltiazem for AF with RVR. Do not give a calcium-channel blocker to treat the overdose of one.
- One adult pill can seriously harm a child. Do not use an adult rule that the child looks fine.
Common errors
- Improvising an insulin infusion.
- Declaring pacing a failure and then stopping all monitoring.
- Giving activated charcoal to a patient who cannot protect the airway.
Practice
One-minute check
Heart rate 38, pressure 70 systolic, empty verapamil bottle. Say what you expect atropine to do, who you call, and which dose you will not invent.
Sources & Further Study
Named guidelines for further study. They are not clinical orders and do not replace your protocol or medical direction.
- AHA 2025 Special Circumstances — toxicologic bradycardia and shock are special circumstances, not routine atropine success
- NASEMSO National Model EMS Clinical Guidelines (2022) — calcium, glucagon, and insulin therapy stay on the local toxicology card
Education only. Apply learning within your protocols and medical direction. This is not clinical care guidance.
Check Your Understanding
Questions drawn only from this lesson. After you check, the key is highlighted. Education practice — not a certification exam.