Chemotherapy: pemetrexed vitamin supplementation: 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 · Chemotherapy: pemetrexed vitamin supplementation

Sample item

Folic acid and vitamin B12 supplementation begins before treatment with a multitargeted antifolate given with cisplatin for non-squamous lung cancer and mesothelioma, in order to reduce its marrow and mucosal toxicity. Which drug is this?

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

The answer and the reasoning

C. Pemetrexed

Pemetrexed inhibits thymidylate synthase, dihydrofolate reductase and GAR formyltransferase. Folic acid and vitamin B12 supplements, often with dexamethasone to prevent rash, lower its haematological and gastrointestinal toxicity without reducing efficacy.

Option by option

  • A. Vinorelbine

    Vinorelbine is a vinca alkaloid whose toxicities are neutropenia and neuropathy.

  • B. Etoposide

    Etoposide is a topoisomerase II inhibitor and needs no vitamin supplementation.

  • C. Pemetrexed (correct)

    Correct. Pemetrexed is an antifolate that needs folic acid and B12 supplementation.

  • D. Gemcitabine

    Gemcitabine is a pyrimidine analogue and does not need vitamin supplementation.

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, Pemetrexed. Pemetrexed inhibits thymidylate synthase, dihydrofolate reductase and GAR formyltransferase.

Why is "Vinorelbine" not the answer?

Vinorelbine is a vinca alkaloid whose toxicities are neutropenia and neuropathy.

Why is "Etoposide" not the answer?

Etoposide is a topoisomerase II inhibitor and needs no vitamin supplementation.

Why is "Gemcitabine" not the answer?

Gemcitabine is a pyrimidine analogue and does not need vitamin supplementation.

What concept does this question test?

It tests Chemotherapy: pemetrexed vitamin supplementation in Pharmacology. Folic acid and vitamin B12 supplements, often with dexamethasone to prevent rash, lower its haematological and gastrointestinal toxicity without reducing efficacy.

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 Chemotherapy: pemetrexed vitamin supplementation?

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.