Mycology: voriconazole interactions: practice question

A Microbiology 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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Microbiology · Mycology: voriconazole interactions

Sample item

A kidney transplant recipient on tacrolimus is started on voriconazole for invasive aspergillosis. Tacrolimus trough levels rise sharply and creatinine increases. What is the mechanism?

AVoriconazole competes with tacrolimus for renal tubular secretionBVoriconazole inhibits CYP3A4 and reduces tacrolimus metabolismCVoriconazole induces CYP3A4 and speeds tacrolimus clearanceDVoriconazole has no effect because it is cleared by the kidney

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

The answer and the reasoning

B. Voriconazole inhibits CYP3A4 and reduces tacrolimus metabolism

Azole antifungals inhibit cytochrome P450 enzymes, particularly CYP3A4, and voriconazole also inhibits CYP2C19 and CYP2C9. Calcineurin inhibitors and sirolimus are CYP3A4 substrates, so their levels rise and doses must be reduced with monitoring. Other voriconazole effects include visual disturbance, hepatotoxicity and phototoxicity.

Option by option

A. Voriconazole competes with tacrolimus for renal tubular secretion
Renal tubular secretion is not the key interaction pathway for tacrolimus.
B. Voriconazole inhibits CYP3A4 and reduces tacrolimus metabolism (correct)
Correct. CYP3A4 inhibition raises tacrolimus exposure and nephrotoxicity.
C. Voriconazole induces CYP3A4 and speeds tacrolimus clearance
Induction would lower levels, as seen with rifampicin, and is the opposite of what occurred.
D. Voriconazole has no effect because it is cleared by the kidney
Voriconazole is metabolised in the liver, and interactions are clinically important.

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.

Questions about this Microbiology question

What is the answer to this Microbiology question?

The best answer is B, Voriconazole inhibits CYP3A4 and reduces tacrolimus metabolism. Azole antifungals inhibit cytochrome P450 enzymes, particularly CYP3A4, and voriconazole also inhibits CYP2C19 and CYP2C9.

Why is "Voriconazole competes with tacrolimus for renal tubular secretion" not the answer?

Renal tubular secretion is not the key interaction pathway for tacrolimus.

Why is "Voriconazole induces CYP3A4 and speeds tacrolimus clearance" not the answer?

Induction would lower levels, as seen with rifampicin, and is the opposite of what occurred.

Why is "Voriconazole has no effect because it is cleared by the kidney" not the answer?

Voriconazole is metabolised in the liver, and interactions are clinically important.

What concept does this question test?

It tests Mycology: voriconazole interactions in Microbiology. Calcineurin inhibitors and sirolimus are CYP3A4 substrates, so their levels rise and doses must be reduced with monitoring. Other voriconazole effects include visual disturbance, hepatotoxicity and phototoxicity.

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 Mycology: voriconazole interactions?

Make a one-line identity card for each organism: shape and stain, defining test, toxin, disease and drug. Then use the flashcards and the other Microbiology 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.