Digitoxin is a cardiac glycoside used primarily for the treatment of heart failure and certain arrhythmias.
It is a medication derived from foxglove plants.
It is structurally related to digoxin and exerts similar pharmacodynamic effects, including positive inotropy of increased myocardial contractility, negative chronotropy with reduced heart rate, and negative dromotropy-slowed conduction through the AV node).
Digitoxin differs from digoxin in its pharmacokinetics: digitoxin is more lipophilic, has higher plasma protein binding, and is mainly eliminated via hepatic metabolism and enterohepatic excretion, making it less dependent on renal function for clearance.
It has a longer half-life (5-7 days vs. 1-2 days for digoxin).
This allows for more stable serum concentrations in patients with renal impairment, and digitoxin does not accumulate in kidney dysfunction as digoxin does.
Its longer half-life also means it takes longer to reach steady-state levels.
It has been used for heart failure and atrial fibrillation, especially in patients with renal dysfunction.
Recent studies suggest digitoxin may reduce the combined risk of death or hospital admission for worsening heart failure in patients with reduced ejection fraction.
Digitoxin has evidence for anti-cancer and anti-angiogenic properties, but its primary indication remains cardiac disease.
Toxicity profiles are similar to other cardiac glycosides, with risks of gastrointestinal symptoms, arrhythmias, visual disturbances, and neuropsychiatric effects in overdose.
Manymedications can affect digitoxin levels.
Blood levels need to be monitored carefully.