CNS drugs and antiepileptics: cyproheptadine in serotonin syndrome: 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 · CNS drugs and antiepileptics: cyproheptadine in serotonin syndrome

Sample item

A man on sertraline is given linezolid for an infection. Within hours he is agitated and sweating, with temperature 39 C, inducible ankle clonus and brisk reflexes. Both drugs are stopped and benzodiazepines are given, but symptoms persist. Which drug is added as a serotonin antagonist?

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

The answer and the reasoning

C. Cyproheptadine

Serotonin syndrome from combining an SSRI with a monoamine oxidase inhibitor such as linezolid is managed by stopping the drugs, giving fluids and benzodiazepines, and cyproheptadine if moderate symptoms persist. Cyproheptadine is a 5-HT2A and H1 antagonist given orally or by tube.

Option by option

  • A. Ondansetron

    Ondansetron blocks 5-HT3 receptors, which do not drive the toxidrome, so it is not an antidote.

  • B. Dantrolene

    Dantrolene acts on skeletal muscle ryanodine receptors and does not help in serotonin toxicity.

  • C. Cyproheptadine (correct)

    Correct. Cyproheptadine blocks 5-HT2A receptors and is the usual antidote for persistent serotonin toxicity.

  • D. Propranolol

    Propranolol may mask tachycardia, can worsen hypotension and is not recommended in this syndrome.

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 C, Cyproheptadine. Serotonin syndrome from combining an SSRI with a monoamine oxidase inhibitor such as linezolid is managed by stopping the drugs, giving fluids and benzodiazepines, and cyproheptadine if moderate symptoms persist.

Why is "Ondansetron" not the answer?

Ondansetron blocks 5-HT3 receptors, which do not drive the toxidrome, so it is not an antidote.

Why is "Dantrolene" not the answer?

Dantrolene acts on skeletal muscle ryanodine receptors and does not help in serotonin toxicity.

Why is "Propranolol" not the answer?

Propranolol may mask tachycardia, can worsen hypotension and is not recommended in this syndrome.

What concept does this question test?

It tests CNS drugs and antiepileptics: cyproheptadine in serotonin syndrome in Pharmacology. Cyproheptadine is a 5-HT2A and H1 antagonist given orally or by tube.

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 CNS drugs and antiepileptics: cyproheptadine in serotonin syndrome?

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.