Antipsychotics: thioridazine: 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 · Antipsychotics: thioridazine

Sample item

A patient on thioridazine for schizophrenia is found to have pigmentary retinopathy and a QTc of 520 ms. Which statement is correct?

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

The answer and the reasoning

B. Thioridazine causes dose-related retinal pigmentation and marked QT prolongation, so it is restricted

Thioridazine is associated with irreversible retinal pigmentation at doses above 800 mg a day and with torsades de pointes, and its use has been curtailed. Other QT-prolonging antipsychotics include haloperidol, pimozide and ziprasidone.

Option by option

  • A. Retinopathy is due to chlorpromazine only

    Thioridazine specifically causes retinal pigmentation.

  • B. Thioridazine causes dose-related retinal pigmentation and marked QT prolongation, so it is restricted (correct)

    Correct. Retinopathy and QT prolongation are its hallmarks.

  • C. QT prolongation is a benefit of the drug

    QT prolongation increases arrhythmia risk.

  • D. Thioridazine has the least cardiac effect among antipsychotics

    It has among the highest cardiac risk.

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 B, Thioridazine causes dose-related retinal pigmentation and marked QT prolongation, so it is restricted. Thioridazine is associated with irreversible retinal pigmentation at doses above 800 mg a day and with torsades de pointes, and its use has been curtailed.

Why is "Retinopathy is due to chlorpromazine only" not the answer?

Thioridazine specifically causes retinal pigmentation.

Why is "QT prolongation is a benefit of the drug" not the answer?

QT prolongation increases arrhythmia risk.

Why is "Thioridazine has the least cardiac effect among antipsychotics" not the answer?

It has among the highest cardiac risk.

What concept does this question test?

It tests Antipsychotics: thioridazine in Pharmacology. Other QT-prolonging antipsychotics include haloperidol, pimozide and ziprasidone.

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 Antipsychotics: thioridazine?

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.