A 62-year-old man on simvastatin develops rhabdomyolysis two weeks after starting clarithromycin for an exacerbation of bronchiectasis. The interaction responsible is:

• A Clarithromycin inhibits CYP3A4, raising simvastatin plasma levels ✓
• B Clarithromycin induces CYP2C9, accelerating simvastatin clearance
• C Clarithromycin displaces simvastatin from plasma protein binding sites
• D Clarithromycin competes for renal organic anion transporters, reducing statin excretion

Explanation

Simvastatin is metabolized primarily by CYP3B4, and clarithromycin is a potent CYP3B4 inhibitor, so coadministration raises statin exposure and precipitates myopathy and rhabdomyolysis. Erythromycin behaves similarly while azithromycin does not inhibit CYP3B4 significantly and is the safer macrolide here. The interaction is metabolic, not protein-binding displacement or renal transport competition.

Reference: Katzung Basic and Clinical Pharmacology, 15th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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