Antimicrobials: fidaxomicin for recurrent C. difficile: 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: fidaxomicin for recurrent C. difficile

Sample item

A 72-year-old has a second recurrence of Clostridioides difficile infection after oral vancomycin. A narrow-spectrum macrocyclic antibiotic that inhibits bacterial RNA polymerase and spares most gut flora is chosen. Which drug is this?

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

The answer and the reasoning

C. Fidaxomicin

Fidaxomicin is minimally absorbed, acts locally in the gut and spares Bacteroides, which lowers the recurrence rate compared with vancomycin. Intravenous vancomycin does not reach the colonic lumen in useful amounts, and broad-spectrum agents can worsen the disease.

Option by option

  • A. Oral clindamycin

    Clindamycin is the classic precipitant of C. difficile colitis and would worsen it.

  • B. Oral ciprofloxacin

    Ciprofloxacin is broad-spectrum and a recognised risk factor for C. difficile.

  • C. Fidaxomicin (correct)

    Correct. Fidaxomicin inhibits RNA polymerase and has a narrow spectrum that preserves gut flora.

  • D. Intravenous vancomycin

    Intravenous vancomycin is not excreted into the colon in useful concentrations.

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.

More Pharmacology questions

Questions about this Pharmacology question

What is the answer to this Pharmacology question?

The best answer is C, Fidaxomicin. Fidaxomicin is minimally absorbed, acts locally in the gut and spares Bacteroides, which lowers the recurrence rate compared with vancomycin.

Why is "Oral clindamycin" not the answer?

Clindamycin is the classic precipitant of C. difficile colitis and would worsen it.

Why is "Oral ciprofloxacin" not the answer?

Ciprofloxacin is broad-spectrum and a recognised risk factor for C. difficile.

Why is "Intravenous vancomycin" not the answer?

Intravenous vancomycin is not excreted into the colon in useful concentrations.

What concept does this question test?

It tests Antimicrobials: fidaxomicin for recurrent C. difficile in Pharmacology. Intravenous vancomycin does not reach the colonic lumen in useful amounts, and broad-spectrum agents can worsen the disease.

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: fidaxomicin for recurrent C. difficile?

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.