Antimicrobials: antifungals: 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: antifungals

Sample item

A patient treated for cryptococcal meningitis with conventional amphotericin B develops rising creatinine, hypokalaemia and hypomagnesaemia. What is the underlying cause and a recognised way to reduce it?

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

The answer and the reasoning

D. Distal tubular damage and afferent vasoconstriction; saline loading or switching to a liposomal formulation

Amphotericin B binds membrane sterols and creates pores in renal tubular cells, causing distal tubular wasting of potassium and magnesium and renal vasoconstriction. Sodium loading with saline, electrolyte replacement and lipid or liposomal formulations reduce nephrotoxicity.

Option by option

  • A. Osmotic nephrosis from sucrose; giving mannitol

    Osmotic nephrosis occurs with intravenous immunoglobulin containing sucrose.

  • B. Proximal tubular crystal deposition; alkalinising the urine

    Crystal nephropathy is typical of acyclovir or sulfonamides rather than amphotericin.

  • C. Immune interstitial nephritis; stopping the drug and starting steroids

    Interstitial nephritis is an allergic reaction and does not cause electrolyte wasting typical of this pattern.

  • D. Distal tubular damage and afferent vasoconstriction; saline loading or switching to a liposomal formulation (correct)

    Correct. Tubular toxicity and vasoconstriction explain the findings, and saline or a liposomal formulation lessens them.

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, Distal tubular damage and afferent vasoconstriction; saline loading or switching to a liposomal formulation. Amphotericin B binds membrane sterols and creates pores in renal tubular cells, causing distal tubular wasting of potassium and magnesium and renal vasoconstriction.

Why is "Osmotic nephrosis from sucrose; giving mannitol" not the answer?

Osmotic nephrosis occurs with intravenous immunoglobulin containing sucrose.

Why is "Proximal tubular crystal deposition; alkalinising the urine" not the answer?

Crystal nephropathy is typical of acyclovir or sulfonamides rather than amphotericin.

Why is "Immune interstitial nephritis; stopping the drug and starting steroids" not the answer?

Interstitial nephritis is an allergic reaction and does not cause electrolyte wasting typical of this pattern.

What concept does this question test?

It tests Antimicrobials: antifungals in Pharmacology. Sodium loading with saline, electrolyte replacement and lipid or liposomal formulations reduce nephrotoxicity.

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: antifungals?

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.