Opioids: methadone: 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 · Opioids: methadone

Sample item

A man with opioid dependence is maintained on methadone and develops palpitations and a QTc of 510 ms. Which property of methadone explains the choice for maintenance and the cardiac risk?

AShort half-life and no cardiac effectsBIt is a mu antagonistCIt is a partial agonist with ceiling effect and no QT effectDLong half-life allows once-daily dosing, but it can prolong the QT interval

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

The answer and the reasoning

D. Long half-life allows once-daily dosing, but it can prolong the QT interval

Methadone is a long-acting mu agonist that prevents withdrawal and craving with once-daily dosing, but dose-related QT prolongation and torsades have been reported. Buprenorphine is a partial agonist used as an alternative.

Option by option

A. Short half-life and no cardiac effects
Its half-life is long, and cardiac effects exist.
B. It is a mu antagonist
It is an agonist, not an antagonist.
C. It is a partial agonist with ceiling effect and no QT effect
That describes buprenorphine, and methadone is not a partial agonist.
D. Long half-life allows once-daily dosing, but it can prolong the QT interval (correct)
Correct. A long half-life suits maintenance, but QT prolongation is a risk.

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.

Questions about this Pharmacology question

What is the answer to this Pharmacology question?

The best answer is D, Long half-life allows once-daily dosing, but it can prolong the QT interval. Methadone is a long-acting mu agonist that prevents withdrawal and craving with once-daily dosing, but dose-related QT prolongation and torsades have been reported.

Why is "Short half-life and no cardiac effects" not the answer?

Its half-life is long, and cardiac effects exist.

Why is "It is a mu antagonist" not the answer?

It is an agonist, not an antagonist.

Why is "It is a partial agonist with ceiling effect and no QT effect" not the answer?

That describes buprenorphine, and methadone is not a partial agonist.

What concept does this question test?

It tests Opioids: methadone in Pharmacology. Buprenorphine is a partial agonist used as an alternative.

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 Opioids: methadone?

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.