Repeated USMLE Questions Step 1- 215- Pharmacology

Q- A 28-year-old woman visits her physician for evaluation of bilateral proximal muscle weakness and muscle pain. Her symptoms started last week, and her pain is getting worse. Her records indicate alcohol abuse and cocaine addiction. She is HIV positive and she takes zidovudine. She also takes simvastatin for hypercholesterolemia. A muscle biopsy shows significant changes in mitochondrial histology.

What is the most likely etiology of this patient’s condition

A- Alcohol abuse

B- Cocaine addiction

C- Zidovudine

D- Simvastatin

E- HIV infection

Answer

This patient presents with proximal muscle weakness, myalgia, and mitochondrial changes on muscle biopsy, which are classic signs of mitochondrial myopathy.

Zidovudine, a nucleoside reverse transcriptase inhibitor (NRTI) used in HIV treatment, is well known for causing mitochondrial toxicity. It inhibits mitochondrial DNA polymerase-γ, leading to impaired oxidative phosphorylation and muscle cell damage.

The correct answer is C

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11 thoughts on “Repeated USMLE Questions Step 1- 215- Pharmacology”

  1. Sir could alcohol cause mitochondrial changes since its a mitochondrial poison?

  2. Sir isnt Alcohol a mitochondrial poison too?

  3. Great work sir

  4. We will consider it. Thank you Dr Mudenda Siachifuwe.

  5. It’s it possible to include medicinal chemistry coz I think it helps answer some of these questions

  6. Thank you Shakeel. I appreciate your commitment.

  7. Tanx sir…its a very good of learning and also helpful in prometric exams.

  8. Thank you

  9. I will. Thank you so much

  10. Thanks for publishing this question format ..
    Keep it up sir .

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