Antiretrovirals: tenofovir nephrotoxicity: 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 · Antiretrovirals: tenofovir nephrotoxicity

Sample item

A 42-year-old man has taken a fixed-dose regimen of tenofovir, lamivudine and dolutegravir for three years. He now has glycosuria with normal blood glucose, hypophosphataemia, low serum bicarbonate and mild proteinuria. Which component is most likely responsible?

ALamivudineBIsoniazid preventive therapyCDolutegravirDTenofovir disoproxil

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

The answer and the reasoning

D. Tenofovir disoproxil

Tenofovir disoproxil accumulates in proximal tubular cells and can cause a Fanconi-type syndrome with glycosuria despite normoglycaemia, phosphaturia, bicarbonate loss and reduced kidney function. Renal function and phosphate are monitored, and tenofovir alafenamide or another agent can be substituted. Dolutegravir only raises serum creatinine mildly by blocking tubular secretion.

Option by option

A. Lamivudine
Lamivudine rarely causes renal toxicity and requires only dose adjustment in renal impairment.
B. Isoniazid preventive therapy
Isoniazid causes hepatitis and neuropathy, not Fanconi syndrome.
C. Dolutegravir
Dolutegravir inhibits creatinine secretion without causing a proximal tubulopathy.
D. Tenofovir disoproxil (correct)
Correct. Tenofovir causes proximal tubulopathy with normoglycaemic glycosuria.

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 Pharmacology question

What is the answer to this Pharmacology question?

The best answer is D, Tenofovir disoproxil. Tenofovir disoproxil accumulates in proximal tubular cells and can cause a Fanconi-type syndrome with glycosuria despite normoglycaemia, phosphaturia, bicarbonate loss and reduced kidney function.

Why is "Lamivudine" not the answer?

Lamivudine rarely causes renal toxicity and requires only dose adjustment in renal impairment.

Why is "Isoniazid preventive therapy" not the answer?

Isoniazid causes hepatitis and neuropathy, not Fanconi syndrome.

Why is "Dolutegravir" not the answer?

Dolutegravir inhibits creatinine secretion without causing a proximal tubulopathy.

What concept does this question test?

It tests Antiretrovirals: tenofovir nephrotoxicity in Pharmacology. Renal function and phosphate are monitored, and tenofovir alafenamide or another agent can be substituted. Dolutegravir only raises serum creatinine mildly by blocking tubular secretion.

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 Antiretrovirals: tenofovir nephrotoxicity?

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.