A 42-year-old man with chronic kidney disease (eGFR 28 mL/min/1.73 m²) is prescribed clarithromycin 500 mg twice daily for 7 days to treat a respiratory tract infection. He is also on simvastatin 40 mg daily and verapamil 120 mg twice daily for hypertension. On day 3, he develops severe myalgia, dark urine, and elevated creatine kinase (CK 2800 U/L). What is the most likely mechanism of this adverse event?