Adverse Drug Reactions and Interactions · USMLE Step 1

Which of the following drug–drug combinations should be avoided because of high risk of serious toxicity due to interaction via CYP3A4 inhibition?

  1. Erythromycin + simvastatin
  2. Amoxicillin + metformin
  3. Hydrochlorothiazide + lisinopril
  4. Aspirin + ibuprofen
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Correct answer: Erythromycin + simvastatin

Erythromycin is a known CYP3A4 inhibitor. When combined with simvastatin (metabolized by CYP3A4), it can substantially increase statin levels and risk of rhabdomyolysis or other statin-associated toxicities.

Difficulty: Medium Question 12 of 19

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