Autonomic nervous system: clonidine withdrawal: 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 · Autonomic nervous system: clonidine withdrawal

Sample item

A hypertensive woman stops her clonidine abruptly and within a day has headache, tremor, sweating and a blood pressure of 220/120 mm Hg. What is the basis of this reaction?

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

The answer and the reasoning

B. Rebound noradrenaline release after withdrawal

Chronic clonidine suppresses central sympathetic outflow and noradrenaline release. When the drug is stopped suddenly, the previously inhibited sympathetic system overshoots and a catecholamine surge produces hypertensive crisis. Tapering over days avoids it.

Option by option

  • A. Withdrawal of central dopaminergic tone

    Clonidine does not act through dopaminergic pathways.

  • B. Rebound noradrenaline release after withdrawal (correct)

    Correct. Release of noradrenaline rebounds once the alpha-2 brake is removed.

  • C. Upregulated muscarinic receptors in the vessels

    Clonidine does not act on muscarinic receptors, and their upregulation does not explain the crisis.

  • D. Rebound activity of the renin-angiotensin system alone

    The rise in catecholamines, not the renin system alone, is the main mechanism.

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 Pharmacology question

What is the answer to this Pharmacology question?

The best answer is B, Rebound noradrenaline release after withdrawal. Chronic clonidine suppresses central sympathetic outflow and noradrenaline release.

Why is "Withdrawal of central dopaminergic tone" not the answer?

Clonidine does not act through dopaminergic pathways.

Why is "Upregulated muscarinic receptors in the vessels" not the answer?

Clonidine does not act on muscarinic receptors, and their upregulation does not explain the crisis.

Why is "Rebound activity of the renin-angiotensin system alone" not the answer?

The rise in catecholamines, not the renin system alone, is the main mechanism.

What concept does this question test?

It tests Autonomic nervous system: clonidine withdrawal in Pharmacology. When the drug is stopped suddenly, the previously inhibited sympathetic system overshoots and a catecholamine surge produces hypertensive crisis. Tapering over days avoids it.

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 Autonomic nervous system: clonidine withdrawal?

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.