Major
amiodarone × atorvastatin
Class III antiarrhythmics (Vaughan Williams)×HMG-CoA reductase inhibitors (statins)
Mechanism
Amiodarone inhibits CYP3A4, which partially metabolizes atorvastatin. Atorvastatin concentration rises and myopathy risk increases. The effect is less dramatic than for simvastatin or lovastatin but is clinically meaningful.
Management
Cap atorvastatin at ≤ 40 mg/day. If muscle pain appears, check CK and temporarily withhold the statin. Alternatives include pravastatin or rosuvastatin (not CYP3A4-metabolized).
Sources
- Lexicomp: Lexicomp Drug Interactions (2024)— Wolters Kluwer Clinical Drug Information, Inc. Lexi-Interact Online, 2024
- Pharmaceutical Press: Stockley's Drug Interactions, 12th edition (2024)— Preston CL (ed.). Stockley's Drug Interactions. 12th ed. London: Pharmaceutical Press; 2024