Pituitary drugs: pegvisomant: 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 · Pituitary drugs: pegvisomant

Sample item

A man with acromegaly has persistently raised IGF-1 after incomplete surgery and while on a somatostatin analogue. Pegvisomant is added. How should therapy be monitored?

ABy serum GH, because it should fall to normalBBy serum cortisol, because it blocks ACTH releaseCBy serum prolactin, because it is a dopamine agonistDBy serum IGF-1, because the drug blocks the GH receptor and GH assays become unreliable

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

The answer and the reasoning

D. By serum IGF-1, because the drug blocks the GH receptor and GH assays become unreliable

Pegvisomant is a pegylated GH analogue that antagonises the growth hormone receptor, lowering hepatic IGF-1 production. Since it does not lower GH (GH may rise and cross-react in assays), control is monitored by IGF-1. Liver enzymes are checked because transaminases may rise.

Option by option

A. By serum GH, because it should fall to normal
GH can stay high or rise during therapy, so it cannot guide dosing.
B. By serum cortisol, because it blocks ACTH release
It does not act on ACTH release or cortisol.
C. By serum prolactin, because it is a dopamine agonist
It is not a dopamine agonist, so prolactin is not the marker.
D. By serum IGF-1, because the drug blocks the GH receptor and GH assays become unreliable (correct)
Correct. IGF-1 reflects receptor blockade, whereas GH levels are not a reliable marker.

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, By serum IGF-1, because the drug blocks the GH receptor and GH assays become unreliable. Pegvisomant is a pegylated GH analogue that antagonises the growth hormone receptor, lowering hepatic IGF-1 production.

Why is "By serum GH, because it should fall to normal" not the answer?

GH can stay high or rise during therapy, so it cannot guide dosing.

Why is "By serum cortisol, because it blocks ACTH release" not the answer?

It does not act on ACTH release or cortisol.

Why is "By serum prolactin, because it is a dopamine agonist" not the answer?

It is not a dopamine agonist, so prolactin is not the marker.

What concept does this question test?

It tests Pituitary drugs: pegvisomant in Pharmacology. Since it does not lower GH (GH may rise and cross-react in assays), control is monitored by IGF-1. Liver enzymes are checked because transaminases may rise.

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 Pituitary drugs: pegvisomant?

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.