Antibiotics: tetracycline in renal failure: 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 · Antibiotics: tetracycline in renal failure

Sample item

A 62-year-old woman with CKD (eGFR 20 mL/min) has fever and an axillary eschar, and scrub typhus is suspected. Which tetracycline can be used without dose reduction?

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

The answer and the reasoning

B. Doxycycline

Doxycycline is excreted mainly in bile and faeces and is not significantly accumulated in renal failure. Older tetracyclines are cleared by the kidney and have an anti-anabolic effect that raises blood urea and worsens azotaemia. Demeclocycline additionally causes nephrogenic diabetes insipidus.

Option by option

  • A. Oxytetracycline

    Oxytetracycline accumulates in renal impairment and worsens azotaemia.

  • B. Doxycycline (correct)

    Correct. Non-renal elimination makes doxycycline safe in reduced eGFR.

  • C. Demeclocycline

    Demeclocycline is nephrotoxic and causes nephrogenic diabetes insipidus.

  • D. Tetracycline

    Tetracycline accumulates and has an anti-anabolic effect that raises urea.

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 B, Doxycycline. Doxycycline is excreted mainly in bile and faeces and is not significantly accumulated in renal failure.

Why is "Oxytetracycline" not the answer?

Oxytetracycline accumulates in renal impairment and worsens azotaemia.

Why is "Demeclocycline" not the answer?

Demeclocycline is nephrotoxic and causes nephrogenic diabetes insipidus.

Why is "Tetracycline" not the answer?

Tetracycline accumulates and has an anti-anabolic effect that raises urea.

What concept does this question test?

It tests Antibiotics: tetracycline in renal failure in Pharmacology. Older tetracyclines are cleared by the kidney and have an anti-anabolic effect that raises blood urea and worsens azotaemia. Demeclocycline additionally causes nephrogenic diabetes insipidus.

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 Antibiotics: tetracycline in renal failure?

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.