Adrenergic drugs: 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 · Adrenergic drugs

Sample item

A patient with a catecholamine-secreting phaeochromocytoma is being prepared for surgery. Which drug should be started first to control blood pressure?

AClonidineBPropranololCPhenoxybenzamineDHydrochlorothiazide

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

The answer and the reasoning

C. Phenoxybenzamine

Alpha-adrenergic blockade with phenoxybenzamine, a non-competitive blocker, is started first and a beta-blocker is added later only if tachycardia persists. Giving a beta-blocker first removes beta-mediated vasodilatation and leaves alpha vasoconstriction unopposed, risking a hypertensive crisis.

Option by option

A. Clonidine
Clonidine reduces central sympathetic outflow but does not reliably block the effects of tumour-released catecholamines at receptors.
B. Propranolol
Propranolol first leaves alpha-mediated vasoconstriction unopposed and can precipitate a hypertensive crisis.
C. Phenoxybenzamine (correct)
Correct. Alpha blockade comes first to control vasoconstriction and permit volume expansion.
D. Hydrochlorothiazide
A thiazide does not block catecholamine receptors and would worsen volume depletion in these patients.

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 C, Phenoxybenzamine. Alpha-adrenergic blockade with phenoxybenzamine, a non-competitive blocker, is started first and a beta-blocker is added later only if tachycardia persists.

Why is "Clonidine" not the answer?

Clonidine reduces central sympathetic outflow but does not reliably block the effects of tumour-released catecholamines at receptors.

Why is "Propranolol" not the answer?

Propranolol first leaves alpha-mediated vasoconstriction unopposed and can precipitate a hypertensive crisis.

Why is "Hydrochlorothiazide" not the answer?

A thiazide does not block catecholamine receptors and would worsen volume depletion in these patients.

What concept does this question test?

It tests Adrenergic drugs in Pharmacology. Giving a beta-blocker first removes beta-mediated vasodilatation and leaves alpha vasoconstriction unopposed, risking a hypertensive crisis.

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 Adrenergic drugs?

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.