Epidemiology: phase IV post-marketing surveillance: practice question

A PSM 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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PSM · Epidemiology: phase IV post-marketing surveillance

Sample item

Two years after a new anticoagulant is licensed and widely prescribed, a rare liver injury occurring in about 1 in 20,000 users is reported. Which stage of drug evaluation is designed to detect such rare adverse effects?

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

The answer and the reasoning

C. Phase IV

Phase IV is post-marketing surveillance after licensure, in large unselected populations over long periods. Rare or delayed adverse reactions that earlier trials were too small to reveal are picked up here.

Option by option

  • A. Phase I

    Phase I studies are small and look at safety and tolerance in a few volunteers, far too few to see a 1 in 20,000 event.

  • B. Phase III

    Phase III trials involve hundreds to a few thousand patients, which is still too few to detect an event this rare.

  • C. Phase IV (correct)

    Correct. Phase IV follows a drug into general use and detects rare and late adverse effects.

  • D. Phase II

    Phase II studies are small trials in patients, again too small to detect such rare effects.

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.

More PSM questions

Questions about this PSM question

What is the answer to this PSM question?

The best answer is C, Phase IV. Phase IV is post-marketing surveillance after licensure, in large unselected populations over long periods.

Why is "Phase I" not the answer?

Phase I studies are small and look at safety and tolerance in a few volunteers, far too few to see a 1 in 20,000 event.

Why is "Phase III" not the answer?

Phase III trials involve hundreds to a few thousand patients, which is still too few to detect an event this rare.

Why is "Phase II" not the answer?

Phase II studies are small trials in patients, again too small to detect such rare effects.

What concept does this question test?

It tests Epidemiology: phase IV post-marketing surveillance in PSM. Rare or delayed adverse reactions that earlier trials were too small to reveal are picked up here.

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 Epidemiology: phase IV post-marketing surveillance?

Practise biostatistics with small calculations until sensitivity, predictive values and risk measures are automatic. Then use the flashcards and the other PSM 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.