Endocrine drugs: atosiban tocolysis: 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 · Endocrine drugs: atosiban tocolysis

Sample item

A woman at 30 weeks in preterm labour has severe cardiac disease, so a beta-agonist and nifedipine are avoided. Atosiban is chosen. Atosiban inhibits uterine contractions by antagonising which receptor?

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

The answer and the reasoning

A. Oxytocin receptor

Atosiban is a competitive antagonist of oxytocin receptors (with some vasopressin V1a activity) in the myometrium, reducing contractions with few maternal cardiovascular effects. Beta-2 agonists cause tachycardia and pulmonary oedema, nifedipine blocks calcium channels, and indomethacin inhibits prostaglandin synthesis.

Option by option

  • A. Oxytocin receptor (correct)

    Correct. Atosiban blocks the oxytocin receptor.

  • B. L-type calcium channel

    Calcium channel blockade is the action of nifedipine.

  • C. Beta-2 adrenergic receptor

    Beta-2 receptor stimulation is the action of terbutaline and ritodrine.

  • D. Cyclo-oxygenase-2 enzyme

    Cyclo-oxygenase inhibition is the action of indomethacin.

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 A, Oxytocin receptor. Atosiban is a competitive antagonist of oxytocin receptors (with some vasopressin V1a activity) in the myometrium, reducing contractions with few maternal cardiovascular effects.

Why is "L-type calcium channel" not the answer?

Calcium channel blockade is the action of nifedipine.

Why is "Beta-2 adrenergic receptor" not the answer?

Beta-2 receptor stimulation is the action of terbutaline and ritodrine.

Why is "Cyclo-oxygenase-2 enzyme" not the answer?

Cyclo-oxygenase inhibition is the action of indomethacin.

What concept does this question test?

It tests Endocrine drugs: atosiban tocolysis in Pharmacology. Beta-2 agonists cause tachycardia and pulmonary oedema, nifedipine blocks calcium channels, and indomethacin inhibits prostaglandin synthesis.

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 Endocrine drugs: atosiban tocolysis?

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.