Antimicrobials: cidofovir and probenecid: 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 · Antimicrobials: cidofovir and probenecid

Sample item

Which anti-CMV drug must be given with probenecid and intravenous saline pre-hydration to limit proximal tubular toxicity?

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

The answer and the reasoning

D. Cidofovir

Cidofovir is taken up into proximal tubular cells by the organic anion transporter, causing nephrotoxicity. Probenecid blocks this uptake, and saline hydration lowers the risk further. Foscarnet also needs saline loading but not probenecid.

Option by option

  • A. Ganciclovir

    Ganciclovir causes bone marrow suppression rather than a dependence on probenecid.

  • B. Foscarnet

    Foscarnet needs hydration but is not given with probenecid.

  • C. Letermovir

    Letermovir is an oral terminase inhibitor used for prophylaxis and has little renal toxicity.

  • D. Cidofovir (correct)

    Correct. Probenecid blocks tubular uptake of cidofovir and reduces nephrotoxicity.

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 D, Cidofovir. Cidofovir is taken up into proximal tubular cells by the organic anion transporter, causing nephrotoxicity.

Why is "Ganciclovir" not the answer?

Ganciclovir causes bone marrow suppression rather than a dependence on probenecid.

Why is "Foscarnet" not the answer?

Foscarnet needs hydration but is not given with probenecid.

Why is "Letermovir" not the answer?

Letermovir is an oral terminase inhibitor used for prophylaxis and has little renal toxicity.

What concept does this question test?

It tests Antimicrobials: cidofovir and probenecid in Pharmacology. Probenecid blocks this uptake, and saline hydration lowers the risk further. Foscarnet also needs saline loading but not probenecid.

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 Antimicrobials: cidofovir and probenecid?

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.