Antimicrobials: nitrofurantoin: 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: nitrofurantoin

Sample item

A woman at 38 weeks of pregnancy and an elderly woman with eGFR 20 mL/min both have cystitis. Why is nitrofurantoin a poor choice in these two?

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

The answer and the reasoning

A. Risk of neonatal haemolysis near term, and inadequate urinary concentration with toxicity at low GFR

Nitrofurantoin is active against common cystitis pathogens but needs adequate renal function to achieve urinary concentration, and with low GFR there is treatment failure and neuropathy. It is avoided near term because of the risk of haemolysis in G6PD-deficient infants.

Option by option

  • A. Risk of neonatal haemolysis near term, and inadequate urinary concentration with toxicity at low GFR (correct)

    Correct. Both concerns are recognised.

  • B. It is not active against E. coli

    It is active against E. coli.

  • C. It causes grey baby syndrome

    Grey baby syndrome is related to chloramphenicol.

  • D. It causes nephrotoxicity by crystalluria

    Crystalluria is associated with sulfonamides and aciclovir.

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 A, Risk of neonatal haemolysis near term, and inadequate urinary concentration with toxicity at low GFR. Nitrofurantoin is active against common cystitis pathogens but needs adequate renal function to achieve urinary concentration, and with low GFR there is treatment failure and neuropathy.

Why is "It is not active against E. coli" not the answer?

It is active against E. coli.

Why is "It causes grey baby syndrome" not the answer?

Grey baby syndrome is related to chloramphenicol.

Why is "It causes nephrotoxicity by crystalluria" not the answer?

Crystalluria is associated with sulfonamides and aciclovir.

What concept does this question test?

It tests Antimicrobials: nitrofurantoin in Pharmacology. It is avoided near term because of the risk of haemolysis in G6PD-deficient infants.

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 Antimicrobials: nitrofurantoin?

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.