Local anaesthetics: lignocaine as antiarrhythmic: practice question

A Anaesthesia 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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Anaesthesia · Local anaesthetics: lignocaine as antiarrhythmic

Sample item

Intravenous lignocaine is used for ventricular arrhythmias. To which class of antiarrhythmic does it belong?

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

The answer and the reasoning

D. Class Ib sodium channel blocker

Lignocaine blocks sodium channels in a use-dependent manner and shortens the action potential, with the greatest effect in depolarised, ischaemic ventricular tissue. It is a class Ib agent and is not useful for atrial arrhythmias. It also blunts the pressor response to laryngoscopy.

Option by option

  • A. Class Ia sodium channel blocker

    Class Ia includes quinidine and procainamide, which prolong the action potential.

  • B. Class IV calcium channel blocker

    Class IV drugs are calcium channel blockers.

  • C. Class II beta blocker

    Class II drugs are beta blockers.

  • D. Class Ib sodium channel blocker (correct)

    Correct. Lignocaine is a class Ib agent.

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 Anaesthesia question

What is the answer to this Anaesthesia question?

The best answer is D, Class Ib sodium channel blocker. Lignocaine blocks sodium channels in a use-dependent manner and shortens the action potential, with the greatest effect in depolarised, ischaemic ventricular tissue.

Why is "Class Ia sodium channel blocker" not the answer?

Class Ia includes quinidine and procainamide, which prolong the action potential.

Why is "Class IV calcium channel blocker" not the answer?

Class IV drugs are calcium channel blockers.

Why is "Class II beta blocker" not the answer?

Class II drugs are beta blockers.

What concept does this question test?

It tests Local anaesthetics: lignocaine as antiarrhythmic in Anaesthesia. It is a class Ib agent and is not useful for atrial arrhythmias. It also blunts the pressor response to laryngoscopy.

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 Local anaesthetics: lignocaine as antiarrhythmic?

Make a table of each agent, its key advantage and its main side effect. Then use the flashcards and the other Anaesthesia 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.