What is the recommended dose of digoxin (digitalis glycoside) for adults with atrial fibrillation or heart failure?

Recommended Digoxin Dosing for Adults with Atrial Fibrillation or Heart Failure

The recommended initial dose of digoxin for adults with atrial fibrillation or heart failure is 0.125-0.25 mg daily, with lower doses (0.125 mg daily or every other day) for patients over 70 years, those with impaired renal function, or those with low lean body mass. 1, 2

Initial Dosing Strategy

• For patients under 70 years with normal renal function: 0.25 mg once daily 1, 2
• For patients over 70 years or with impaired renal function: 0.125 mg once daily 1, 2
• For patients with marked renal impairment (GFR <30 mL/min): 0.0625 mg daily 1, 3

Dosing Based on Clinical Condition

Heart Failure

• Target serum concentration should be maintained between 0.5-0.9 ng/mL, as concentrations above 1.0 ng/mL have not shown superior outcomes and may increase mortality risk 4, 1
• Higher doses of digoxin (0.375-0.50 mg daily) are rarely needed or recommended for heart failure management 4, 5
• Loading doses are not necessary for chronic heart failure management 4, 5

Atrial Fibrillation

• For rate control in atrial fibrillation, digoxin is typically used in combination with beta-blockers 1, 4
• For rapid digitalization in atrial fibrillation with rapid ventricular rate, an IV loading dose may be considered: 0.25-0.5 mg IV bolus initially, followed by additional doses of 0.25 mg at 6-8 hour intervals up to a maximum of 1.0 mg over 24 hours 4

Dose Adjustments for Special Populations

• For patients with GFR 30-60 mL/min: reduce dose by 25-50% (typically 0.0625-0.125 mg daily) 3
• For patients with GFR 15-30 mL/min: reduce dose by 50-75% (typically 0.0625 mg daily or every other day) 3
• When used with medications that increase digoxin levels, dose should be reduced:
  • With amiodarone: reduce by 30-50% 1
  • With dronedarone: reduce by at least 50% 1
  • With verapamil, clarithromycin, erythromycin, itraconazole, cyclosporine, propafenone, or quinidine: monitor digoxin levels closely 4, 1

Monitoring Recommendations

• Target serum concentration: 0.5-0.9 ng/mL for heart failure 4, 1
• Serum samples should be drawn just before the next scheduled dose or at least 6-8 hours after the last dose 2
• Monitor serum electrolytes (potassium, magnesium) and renal function regularly 1, 6
• Watch for signs of toxicity: cardiac arrhythmias, gastrointestinal symptoms (anorexia, nausea, vomiting), and neurological complaints (visual disturbances, confusion) 4, 7

Contraindications and Precautions

• Significant sinus or AV block without a permanent pacemaker 4, 1
• Pre-excitation syndromes (e.g., WPW with AF/atrial flutter) 4, 1
• Hypokalemia, hypomagnesemia, or hypothyroidism increase risk of toxicity 4, 7
• Digoxin toxicity is commonly associated with serum levels >2 ng/mL, but may occur at lower levels with electrolyte abnormalities 4, 5

Common Pitfalls and Caveats

• Elderly patients are at increased risk of digoxin toxicity due to reduced renal function and lower lean body mass 7, 6
• Published digoxin dosing nomograms may sometimes result in toxicity; clinical variables need to be closely monitored 7
• Digoxin levels can be affected by many commonly used medications, requiring dose adjustments 4, 1
• For patients with atrial fibrillation and inadequate rate control on digoxin alone, adding another AV nodal blocking agent may be safer than increasing digoxin dose 8
• Serum digoxin concentration may decrease during exercise without any change in clinical efficacy due to increased binding to skeletal muscle 2