What is the recommended dosing for digoxin (Digitalis) in patients with normal renal function and those with impaired renal function?

Digoxin Dosing Recommendations

For patients with heart failure or atrial fibrillation, the recommended digoxin dose is 0.25 mg daily for those with normal renal function, while patients with renal impairment require significant dose reductions based on their level of renal dysfunction. 1, 2

Dosing in Normal Renal Function

• Standard maintenance dose: 0.25 mg daily for adults under 70 years with normal renal function (eGFR >60 mL/min) 1, 2
• Usual maintenance doses range from 0.125-0.25 mg/day 2
• For elderly patients (>70 years) even with normal renal function: 0.125 mg daily 1, 2

Dosing in Renal Impairment

Renal function significantly impacts digoxin dosing requirements:

Renal Function	eGFR	Recommended Dose
Normal	>60 mL/min	0.25 mg daily
Mild impairment	45-59 mL/min	0.125 mg daily
Moderate impairment	30-44 mL/min	0.125 mg daily or every other day
Severe impairment	<30 mL/min	0.0625-0.125 mg every other day

Loading Dose Considerations

When rapid digitalization is needed:

• For patients with normal renal function: A total loading dose of 8-12 mcg/kg 1

  • Administer half initially, followed by 25% fractions at 4-8 hour intervals 1
  • For a 70 kg patient, this typically equals 750-1250 mcg (0.75-1.25 mg) total 2

• For patients with renal impairment:

  • Use more conservative loading doses of 6-10 mcg/kg 1, 3
  • For dialysis-dependent patients, an appropriate intravenous loading dose is 10 mcg/kg 4
  • Patients with creatinine clearance <60 mL/min are at higher risk of toxicity with standard loading doses 3

Special Populations

Elderly Patients

• Starting dose: 0.125 mg daily for patients >70 years 1, 2
• For very elderly or frail patients: Consider 0.0625 mg daily 2

Children

• Infants and young children (under 10 years) generally require proportionally larger doses than adults 2
• Children over 10 years require adult dosages in proportion to their body weight 2

Drug Interactions Requiring Dose Adjustments

• Reduce digoxin dose by 30-50% when co-administered with:

  • Verapamil
  • Clarithromycin
  • Erythromycin
  • Itraconazole
  • Amiodarone 1

• Reduce digoxin dose by at least 50% when co-administered with dronedarone 1

Monitoring

• Therapeutic serum concentration should be between 0.6 and 1.2 ng/mL 5
• Digoxin toxicity is commonly associated with serum levels >2.0 ng/mL 1, 6
• Toxicity can occur at lower levels in the presence of:
  • Hypokalemia
  • Hypomagnesemia
  • Hypothyroidism 1, 6

Contraindications

Digoxin is contraindicated in patients with:

• Second or third-degree heart block without a pacemaker
• Pre-excitation syndromes
• Previous evidence of digoxin intolerance 5
• Wolff-Parkinson-White syndrome with atrial fibrillation 1

Toxicity Management

If digoxin toxicity is suspected:

• Hold digoxin
• Correct electrolyte abnormalities (particularly potassium and magnesium)
• For severe toxicity (serum digoxin >4 ng/mL with serious arrhythmias): Administer digoxin-specific Fab antibody fragments 1

By following these dosing recommendations based on renal function and considering patient-specific factors, clinicians can optimize the efficacy of digoxin therapy while minimizing the risk of toxicity.