Digoxin

Digoxin is a drug that is used primarily to slow the ventricular rate in chronic atrial fibrillation. The use of digoxin may be dangerous in hypertrophic obstructive cardiomyopathy and Wolff-Parkinson-White syndrome.

Digoxin has a weak positive inotropic effect and has been used in the treatment of heart failure in selected patients.

In patients with atrial fibrillation digoxin may be helpful in the symptomatic treatment of heart failure: by controlling the ventricular rate, and thus improving ventricular filling, the myocardium is at a better position on the Frank-Starling curve. However there is no evidence suggesting reduction in mortality in patients who use digoxin (1).

Digoxin also upregulates the baroreceptor reflex and so has a further positive inotropic effect.

Digoxin has a narrow therapeutic ratio (1,2):

• patients with poor renal function, heart failure and diuretic-induced hypokalaemia are more likely to suffer digoxin toxicity

The summary of product characteristics should be consulted before prescribing this drug.

Evidence for the use of a cardiac glycoside in heart failure with reduced ejection fraction (HFrEF) has come from the use of digitoxin in the DIGIT-HF Study (3).

Reference:

• 1) British Heart Foundation (Factfile 7/2001).The use of digoxin.
• (2) Smith TW (1988). Digitalis: mechanism of action and clinical use. NEJM, 318, 358-65.
• (3) Bavendiek U et al; for the DIGIT-HF Study Group. Digitoxin in Patients with Heart Failure and Reduced Ejection Fraction. NEJM 29th August 2025.