Alpha-2 agonists: dexmedetomidine: 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 · Alpha-2 agonists: dexmedetomidine

Sample item

A mechanically ventilated patient in the intensive care unit needs light sedation so that he can be roused and cooperate with assessment. The team wants minimal respiratory depression. Which sedative acts mainly through central alpha-2 receptors at the locus coeruleus?

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

The answer and the reasoning

D. Dexmedetomidine

Dexmedetomidine is a highly selective alpha-2 agonist that reduces noradrenergic firing in the locus coeruleus, giving sedation resembling natural sleep with easy arousability and little respiratory depression. Bradycardia and hypotension are its main adverse effects. Benzodiazepines and propofol act on GABA-A receptors.

Option by option

  • A. Propofol

    Propofol enhances GABA-A function and depresses respiration and blood pressure.

  • B. Ketamine

    Ketamine blocks NMDA receptors and produces dissociation, not arousable sleep-like sedation.

  • C. Midazolam

    Midazolam acts at GABA-A receptors and causes dose-related respiratory depression and delirium.

  • D. Dexmedetomidine (correct)

    Alpha-2 agonism at the locus coeruleus gives arousable sedation with limited respiratory depression.

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 Pharmacology questions

Questions about this Pharmacology question

What is the answer to this Pharmacology question?

The best answer is D, Dexmedetomidine. Dexmedetomidine is a highly selective alpha-2 agonist that reduces noradrenergic firing in the locus coeruleus, giving sedation resembling natural sleep with easy arousability and little respiratory depression.

Why is "Propofol" not the answer?

Propofol enhances GABA-A function and depresses respiration and blood pressure.

Why is "Ketamine" not the answer?

Ketamine blocks NMDA receptors and produces dissociation, not arousable sleep-like sedation.

Why is "Midazolam" not the answer?

Midazolam acts at GABA-A receptors and causes dose-related respiratory depression and delirium.

What concept does this question test?

It tests Alpha-2 agonists: dexmedetomidine in Pharmacology. Bradycardia and hypotension are its main adverse effects. Benzodiazepines and propofol act on GABA-A receptors.

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 Alpha-2 agonists: dexmedetomidine?

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.