Q: 56 year old male with established history of Paroxysmal Atrial fibrillation - on home medications of Digoxin and warfarin is admitted to ICU with A.fib.-RVR (Rapid Ventricular Response). Patient didn't respond to Esmolol or Cardizem IV drips, but to IV bolus and maintenance drip of Amiodarone. What should be a caution?

Answer:  Monitor Digoxin level closely.

Amiodarone will increase the level or effect of digoxin by cationic drug competition for renal tubular clearance, which may cause life-threatening interaction.