Psychotic disorders: clozapine and carbamazepine: 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 · Psychotic disorders: clozapine and carbamazepine

Sample item

A patient with treatment-resistant schizophrenia on clozapine develops generalised seizures. A colleague suggests adding an anticonvulsant that is also a mood stabiliser. Which drug should be avoided in this combination because of additive bone-marrow toxicity?

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

The answer and the reasoning

C. Carbamazepine

Carbamazepine can itself cause agranulocytosis and aplastic anaemia, so it should not be combined with clozapine. Valproate is the usual anticonvulsant choice when seizures complicate clozapine treatment.

Option by option

  • A. Sodium valproate

    Valproate is the commonly used anticonvulsant with clozapine and is not marrow toxic in this way.

  • B. Lamotrigine

    Lamotrigine is not associated with additive agranulocytosis with clozapine.

  • C. Carbamazepine (correct)

    Correct. Carbamazepine adds marrow-suppression risk to clozapine and is also an enzyme inducer.

  • D. Levetiracetam

    Levetiracetam has no recognised haematological interaction with clozapine.

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 C, Carbamazepine. Carbamazepine can itself cause agranulocytosis and aplastic anaemia, so it should not be combined with clozapine.

Why is "Sodium valproate" not the answer?

Valproate is the commonly used anticonvulsant with clozapine and is not marrow toxic in this way.

Why is "Lamotrigine" not the answer?

Lamotrigine is not associated with additive agranulocytosis with clozapine.

Why is "Levetiracetam" not the answer?

Levetiracetam has no recognised haematological interaction with clozapine.

What concept does this question test?

It tests Psychotic disorders: clozapine and carbamazepine in Psychiatry. Valproate is the usual anticonvulsant choice when seizures complicate clozapine treatment.

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 Psychotic disorders: clozapine and carbamazepine?

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.