Substance use: methadone and QT: practice question

A Psychiatry 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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Psychiatry · Substance use: methadone and QT

Sample item

A patient maintained on methadone starts clarithromycin and later has syncope. Which ECG finding is most likely?

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

The answer and the reasoning

C. QT prolongation with torsades de pointes

Methadone prolongs the QT interval and can cause torsades de pointes, particularly at high doses or with CYP3A4 inhibitors such as clarithromycin. An ECG is advised before high doses and when interacting drugs are added. Hypokalaemia and other QT-prolonging drugs add to the risk.

Option by option

  • A. ST depression only

    ST depression alone does not explain methadone-related syncope.

  • B. Peaked T waves with hyperkalaemia

    Peaked T waves occur in hyperkalaemia.

  • C. QT prolongation with torsades de pointes (correct)

    Correct. Methadone with a CYP inhibitor risks QT prolongation and torsades.

  • D. Short PR interval

    Short PR is seen in pre-excitation.

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 Psychiatry question

What is the answer to this Psychiatry question?

The best answer is C, QT prolongation with torsades de pointes. Methadone prolongs the QT interval and can cause torsades de pointes, particularly at high doses or with CYP3A4 inhibitors such as clarithromycin.

Why is "ST depression only" not the answer?

ST depression alone does not explain methadone-related syncope.

Why is "Peaked T waves with hyperkalaemia" not the answer?

Peaked T waves occur in hyperkalaemia.

Why is "Short PR interval" not the answer?

Short PR is seen in pre-excitation.

What concept does this question test?

It tests Substance use: methadone and QT in Psychiatry. An ECG is advised before high doses and when interacting drugs are added. Hypokalaemia and other QT-prolonging drugs add to the risk.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. 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 Substance use: methadone and QT?

Learn each diagnosis by its core features and its first-line treatment. Then use the flashcards and the other Psychiatry 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.