Given the patient's condition of atrial fibrillation and use of the medications Warfarin, Verapamil, and Digoxin, which mechanism best explains why monitoring for digoxin toxicity is important in this patient?
Verapamil can increase digoxin levels by inhibiting its clearance, raising the risk of toxicity. Simvastatin can interact with digoxin to increase its plasma concentration. Clopidogrel reduces the effectiveness of digoxin, requiring dose adjustment. Warfarin and digoxin together increase the risk of bleeding complications.