Pharmacology: phenylephrine: practice question

A Anaesthesia 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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Anaesthesia · Pharmacology: phenylephrine

Sample item

Which effect is characteristic of a phenylephrine bolus?

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

The answer and the reasoning

C. Increased systemic vascular resistance with reflex bradycardia

Phenylephrine is a pure alpha-1 agonist that causes arteriolar and venous constriction. The rise in pressure triggers a baroreceptor reflex bradycardia, and cardiac output may fall with a high dose. It is therefore useful in conditions where tachycardia should be avoided.

Option by option

  • A. Increased heart rate and contractility via beta-1 receptors

    Beta-1 stimulation characterises drugs such as dobutamine and ephedrine.

  • B. Bronchodilation

    Bronchodilation is a beta-2 effect.

  • C. Increased systemic vascular resistance with reflex bradycardia (correct)

    Correct. It constricts vessels and slows the heart reflexly.

  • D. Reduced blood pressure

    It raises blood pressure.

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 Anaesthesia question

What is the answer to this Anaesthesia question?

The best answer is C, Increased systemic vascular resistance with reflex bradycardia. Phenylephrine is a pure alpha-1 agonist that causes arteriolar and venous constriction.

Why is "Increased heart rate and contractility via beta-1 receptors" not the answer?

Beta-1 stimulation characterises drugs such as dobutamine and ephedrine.

Why is "Bronchodilation" not the answer?

Bronchodilation is a beta-2 effect.

Why is "Reduced blood pressure" not the answer?

It raises blood pressure.

What concept does this question test?

It tests Pharmacology: phenylephrine in Anaesthesia. The rise in pressure triggers a baroreceptor reflex bradycardia, and cardiac output may fall with a high dose. It is therefore useful in conditions where tachycardia should be avoided.

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 Pharmacology: phenylephrine?

Make a table of each agent, its key advantage and its main side effect. Then use the flashcards and the other Anaesthesia 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.