Psychopharmacology: carbamazepine induction: practice question

A Psychiatry 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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Psychiatry · Psychopharmacology: carbamazepine induction

Sample item

A woman on carbamazepine for bipolar disorder becomes pregnant while taking the combined oral contraceptive pill. What is the explanation?

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

The answer and the reasoning

B. Enzyme induction accelerates the metabolism of ethinylestradiol

Carbamazepine induces CYP3A4 and reduces the efficacy of oral contraceptives, as well as its own metabolism (autoinduction). Higher-dose pills, alternative methods such as an IUD, or a different mood stabiliser are advised.

Option by option

  • A. Carbamazepine inhibits ovulation

    It does not suppress ovulation reliably.

  • B. Enzyme induction accelerates the metabolism of ethinylestradiol (correct)

    Correct. Enzyme induction lowers contraceptive hormone levels.

  • C. Carbamazepine increases oestrogen levels

    It lowers rather than raises hormone levels.

  • D. The pill is not metabolised

    The pill is metabolised hepatically.

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 Psychiatry question

What is the answer to this Psychiatry question?

The best answer is B, Enzyme induction accelerates the metabolism of ethinylestradiol. Carbamazepine induces CYP3A4 and reduces the efficacy of oral contraceptives, as well as its own metabolism (autoinduction).

Why is "Carbamazepine inhibits ovulation" not the answer?

It does not suppress ovulation reliably.

Why is "Carbamazepine increases oestrogen levels" not the answer?

It lowers rather than raises hormone levels.

Why is "The pill is not metabolised" not the answer?

The pill is metabolised hepatically.

What concept does this question test?

It tests Psychopharmacology: carbamazepine induction in Psychiatry. Higher-dose pills, alternative methods such as an IUD, or a different mood stabiliser are advised.

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 Psychopharmacology: carbamazepine induction?

Learn each diagnosis by its core features and its first-line treatment. Then use the flashcards and the other Psychiatry 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.