What is the recommended dosage of digoxin (digitalis glycoside) for heart failure treatment?

Digoxin 0.25mg Tablet Dosage for Heart Failure

For most adult patients with heart failure and normal renal function under age 70, initiate digoxin at 0.25 mg daily without a loading dose, targeting serum concentrations of 0.5-1.0 ng/mL. 1

Standard Dosing Algorithm

Initial Dose Selection Based on Patient Characteristics

• Patients under 70 years with normal renal function: Start with 0.25 mg daily 1, 2
• Patients over 70 years, impaired renal function, or low lean body mass: Start with 0.125 mg daily 1, 2
• Marked renal impairment (CrCl <30 mL/min): Start with 0.0625 mg daily 3
• Dialysis-dependent patients: Use 0.0625 mg daily or every other day 3

Loading Doses Are Not Recommended

There is no reason to use loading doses of digoxin to initiate therapy in patients with heart failure. 1, 3 The ACC/AHA guidelines explicitly state that loading doses should be avoided, as steady-state concentrations will be achieved in approximately 1-3 weeks depending on renal function, and this gradual accumulation is safer than rapid loading. 1, 3

Target Therapeutic Range

Aim for serum digoxin concentrations of 0.5-1.0 ng/mL (specifically 0.5-0.9 ng/mL), which is lower than historically recommended levels. 1, 3 Retrospective analysis of the Digitalis Investigation Group trial demonstrated that risk-adjusted mortality increased when plasma concentrations exceeded 1.0 ng/mL, and lower concentrations (0.5-0.9 ng/mL) provided equivalent prevention of worsening heart failure. 1

Monitoring Requirements

• Check digoxin levels early during chronic therapy in all patients, with sampling done just before the next scheduled dose or at least 6-8 hours after the last dose 3, 2
• Serial monitoring of serum electrolytes and renal function is mandatory 3
• Routine digoxin level monitoring is not beneficial in stable patients, but should be checked for suspected toxicity, significant changes in renal function, or initiation of interacting medications 3

Critical Dose Adjustments for Drug Interactions

Reduce the digoxin dose by approximately 50% when initiating the following medications, as they significantly increase serum digoxin concentrations: 1, 3, 4

• Amiodarone (consider 0.0625 mg daily if N-desethylamiodarone >600 ng/mL) 5
• Clarithromycin or erythromycin
• Verapamil or diltiazem
• Quinidine
• Itraconazole
• Cyclosporine
• Propafenone
• Dronedarone

Common Pitfalls to Avoid

Electrolyte Disturbances

**Toxicity may occur even with therapeutic digoxin levels if hypokalemia (K+ <4.0 mEq/L), hypomagnesemia, or hypothyroidism coexist.** 1, 4 Maintain potassium >4.0 mEq/L to minimize toxicity risk. 4

Higher Doses Are Rarely Needed

Higher doses (0.375-0.50 mg daily) are rarely used or needed in heart failure management and increase toxicity risk without superior outcomes. 1 The European Society of Cardiology guidelines specify that the usual daily dose is 0.125-0.25 mg for patients with normal serum creatinine. 1

Acute Decompensation

Digoxin is not indicated as primary therapy for stabilization of patients with acute exacerbation of heart failure symptoms. 1 Such patients should first receive appropriate treatment with intravenous medications; digoxin may be initiated after stabilization. 1

Contraindications

Do not administer digoxin to patients with: 1

• Significant sinus or atrioventricular block (unless treated with permanent pacemaker)
• Bradycardia
• Sick sinus syndrome
• Carotid sinus syndrome
• Wolff-Parkinson-White syndrome
• Hypertrophic obstructive cardiomyopathy
• Severe hypokalemia or hyperkalemia

Maintenance Dosing Calculation

For patients requiring precise dose calculation, the FDA label provides a formula based on creatinine clearance: 2

Maintenance Dose = Peak Body Stores × % Daily Loss/100

Where: % Daily Loss = 14 + (CrCl/5)

This formula accounts for the fact that digoxin elimination is primarily renal, and steady-state will be achieved in 1-3 weeks depending on renal function. 2

Signs of Toxicity Requiring Immediate Action

Overt digoxin toxicity is commonly associated with serum levels >2 ng/mL but may occur at lower levels. 1, 4 Manifestations include: 4

• Cardiac: ventricular tachycardia (especially fascicular or bidirectional), enhanced automaticity with AV block
• Gastrointestinal: anorexia, nausea, vomiting
• Neurological: visual disturbances (blurred or yellow vision), confusion, disorientation

For life-threatening toxicity with serious arrhythmias or hyperkalemia, administer digoxin-specific Fab antibody fragments immediately. 3, 4