Risk factors for digoxin toxicity
| Risk factor | Comments |
|---|---|
| Advanced age | Reduced volume of distribution due to lower muscle mass and reduced renal drug clearance can lead to higher serum concentrations of digoxin in the elderly Digoxin use has been linked to higher mortality in patients age 65 and older with atrial fibrillation and heart failure19 |
| Renal dysfunction | Digoxin is primarily excreted by the kidneys and its clearance is directly proportional to the glomerular filtration rate Reduced renal clearance results in higher serum digoxin concentration, and dose should be reduced in patients with renal dysfunction Any condition that leads to acute renal injury (eg, dehydration, sepsis, glomerular or tubular disease, or decompensated heart failure) can predispose to toxicity Digoxin use in patients with end-stage kidney disease undergoing hemodialysis is associated with a 28% increase in mortality and is therefore not recommended20 If needed in end-stage kidney disease, a loading dose of 3 to 5 μg/kg (0.25–0.375 mg) is recommended, followed by a maintenance dose of 0.0625 mg every 48 hours |
| Hypokalemia | Decreased potassium levels result in decreased competition for the binding spot of digoxin in sodium-potassium adenosine triphosphatase, favoring binding of digoxin to the ionic pump17 |
| Drug interactions | Diuretics, antiarrhythmic drugs, and antibiotics can increase serum digoxin concentration or enhance digoxin action17,18 |