As the oldest cardiac glycoside with a narrow therapeutic index and complex pharmacokinetic profile, digoxin is still used to treat many conditions such as congestive heart failure (CHF), atrial fibrillation or flutter, and certain cardiac arrhythmias.1 Its distribution in the heart and muscles might increase due to hyperthyroidism or hypokalaemia and decrease due to hyperkalaemia or hyponatraemia.1 Digoxin is the minor substrate of cytochrome-P450 (CYP) 3A4 and the major substrate of P-glycoprotein/ABCB1.1

In general, the incidence of toxicity is reported to be about 1% in patients with CHF treated with digoxin.1 Increased intracellular calcium due to inhibition of Na–K transporter is the primary pathway of digoxin toxicity.2 Factors such as renal function, …