Toxicology: calcium channel blocker overdose: practice question

A Forensic Medicine question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Forensic Medicine · Toxicology: calcium channel blocker overdose

Sample item

A man on verapamil for an arrhythmia swallows a large number of tablets. He has bradycardia, hypotension and a raised blood glucose. Which drug is given as the first-line antidote?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

D. Intravenous calcium gluconate

Calcium channel blockade reduces calcium entry into myocardial and vascular smooth muscle cells. Intravenous calcium raises the extracellular gradient and improves contractility and blood pressure, and high-dose insulin and vasopressors are used when the response is poor. Hyperglycaemia arises because insulin release is also calcium dependent.

Option by option

  • A. Intravenous sodium bicarbonate

    Bicarbonate is used for sodium channel blocking agents such as tricyclic antidepressants.

  • B. Intravenous physostigmine

    Physostigmine treats anticholinergic poisoning and could worsen bradycardia.

  • C. Intravenous naloxone

    Naloxone reverses opioids only.

  • D. Intravenous calcium gluconate (correct)

    Correct. Calcium overcomes the channel blockade and restores contractility.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

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Questions about this Forensic Medicine question

What is the answer to this Forensic Medicine question?

The best answer is D, Intravenous calcium gluconate. Calcium channel blockade reduces calcium entry into myocardial and vascular smooth muscle cells.

Why is "Intravenous sodium bicarbonate" not the answer?

Bicarbonate is used for sodium channel blocking agents such as tricyclic antidepressants.

Why is "Intravenous physostigmine" not the answer?

Physostigmine treats anticholinergic poisoning and could worsen bradycardia.

Why is "Intravenous naloxone" not the answer?

Naloxone reverses opioids only.

What concept does this question test?

It tests Toxicology: calcium channel blocker overdose in Forensic Medicine. Intravenous calcium raises the extracellular gradient and improves contractility and blood pressure, and high-dose insulin and vasopressors are used when the response is poor. Hyperglycaemia arises because insulin release is also calcium dependent.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Toxicology: calcium channel blocker overdose?

Learn postmortem changes with their timelines, and toxicology as poison, sign, test and antidote. Then use the flashcards and the other Forensic Medicine questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.