Antiarrhythmics: class IC drugs after myocardial infarction: practice question

A Pharmacology 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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Pharmacology · Antiarrhythmics: class IC drugs after myocardial infarction

Sample item

A 62-year-old man two weeks after anterior myocardial infarction with an ejection fraction of 35 percent has frequent asymptomatic ventricular premature beats. A colleague suggests flecainide to suppress them. Why is this inappropriate?

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

The answer and the reasoning

D. Class IC drugs increased mortality in post-infarction patients in the CAST trial

The Cardiac Arrhythmia Suppression Trial showed that flecainide and encainide, given to suppress ventricular ectopy after infarction, increased mortality through proarrhythmia in scarred myocardium. Class IC agents (flecainide, propafenone) are therefore avoided in structural heart disease and ischaemia. Beta-blockers improve outcome in this setting.

Option by option

  • A. Flecainide causes pulmonary fibrosis within weeks

    Pulmonary fibrosis is a typical amiodarone adverse effect.

  • B. Flecainide acts as a class III agent that triggers torsades de pointes

    Flecainide is a potent sodium channel blocker of class IC, not a class III potassium channel blocker.

  • C. Flecainide is ineffective against ventricular ectopy

    Flecainide does suppress ventricular ectopy, which is why CAST tested it.

  • D. Class IC drugs increased mortality in post-infarction patients in the CAST trial (correct)

    Correct. Suppressing ectopy with class IC drugs after infarction worsened survival.

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 Pharmacology question

What is the answer to this Pharmacology question?

The best answer is D, Class IC drugs increased mortality in post-infarction patients in the CAST trial. The Cardiac Arrhythmia Suppression Trial showed that flecainide and encainide, given to suppress ventricular ectopy after infarction, increased mortality through proarrhythmia in scarred myocardium.

Why is "Flecainide causes pulmonary fibrosis within weeks" not the answer?

Pulmonary fibrosis is a typical amiodarone adverse effect.

Why is "Flecainide acts as a class III agent that triggers torsades de pointes" not the answer?

Flecainide is a potent sodium channel blocker of class IC, not a class III potassium channel blocker.

Why is "Flecainide is ineffective against ventricular ectopy" not the answer?

Flecainide does suppress ventricular ectopy, which is why CAST tested it.

What concept does this question test?

It tests Antiarrhythmics: class IC drugs after myocardial infarction in Pharmacology. Class IC agents (flecainide, propafenone) are therefore avoided in structural heart disease and ischaemia. Beta-blockers improve outcome in this setting.

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 Antiarrhythmics: class IC drugs after myocardial infarction?

Learn drugs as classes, then the exception in each class that an examiner would pick. Then use the flashcards and the other Pharmacology 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.