Moderate
Atorvastatin × Verapamil
HMG-CoA reductase inhibitors (statins)×Non-dihydropyridine calcium channel blocker
Mechanism
Verapamil is a moderate CYP3A4 inhibitor. Atorvastatin plasma levels rise 2-fold, raising myalgia risk.
Symptoms
Pain and weakness in large muscle groups (thighs, shoulders, calves), dark urine, elevated creatine kinase. Symptoms usually appear 2–6 weeks after starting the combination.
Management
Cap atorvastatin at 20 mg/day when combined. If LDL targets are missed, switch to pravastatin or rosuvastatin. Alternative to verapamil: amlodipine or a beta-blocker.