Can digoxin be used in patients undergoing Continuous Ambulatory Peritoneal Dialysis (CAPD)?

Digoxin Use in CAPD Patients

Digoxin can be used in patients undergoing Continuous Ambulatory Peritoneal Dialysis (CAPD), but requires dose adjustment and careful monitoring due to altered pharmacokinetics and increased risk of toxicity.

Pharmacokinetic Considerations in CAPD

• Patients with renal failure, including those on CAPD, have a reduced apparent volume of distribution of digoxin (approximately one-third lower than individuals with normal renal function), which increases risk of toxicity 1
• Peritoneal dialysis does not effectively remove digoxin from the systemic circulation, even when performed on an intensive schedule 2
• Digoxin clearance is primarily renal, and impaired renal function is a common risk factor for toxicity 2

Dosing Recommendations

• Lower initial doses should be used in CAPD patients:

  • Starting dose of 0.125 mg daily or every other day is recommended 3
  • Loading doses are generally not required in stable patients 3
  • If an intravenous loading dose is needed, approximately 10 μg/kg may be appropriate in patients with advanced renal failure 4

• Maintenance dosing should be individualized based on:

  • Patient's age (lower doses if >70 years) 3
  • Body mass (lower doses if low lean body mass) 3
  • Renal function 3

Monitoring Requirements

• Regular monitoring of serum digoxin levels is mandatory in CAPD patients 3
• Target serum concentration should be in the range of 0.5-0.9 ng/mL 3
• Levels above 2 ng/mL are commonly associated with overt toxicity, but toxicity may occur at lower levels in patients with renal impairment 3
• Regular monitoring of serum electrolytes (especially potassium and magnesium) and renal function is essential 3

Potential Adverse Effects and Precautions

• Major adverse effects include:

  • Cardiac arrhythmias (ectopic rhythms, heart block) 3
  • Gastrointestinal symptoms (anorexia, nausea, vomiting) 3
  • Neurological complaints (visual disturbances, disorientation, confusion) 3

• Risk factors for digoxin toxicity in CAPD patients:

  • Electrolyte disturbances (hypokalemia, hypomagnesemia) 3
  • Hypothyroidism 3
  • Drug interactions (clarithromycin, erythromycin, amiodarone, itraconazole, cyclosporine, verapamil, quinidine) 3

Clinical Indications in CAPD Patients

• Digoxin may be considered in CAPD patients with:

  • Symptomatic heart failure with reduced ejection fraction (HFrEF) despite guideline-directed medical therapy 3
  • Atrial fibrillation with rapid ventricular response 3, 5

• For heart failure management:

  • Digoxin has been downgraded from Class I to Class IIa/IIb recommendation in heart failure guidelines 3
  • It may reduce hospitalizations but has no mortality benefit 3, 5
  • Should be considered after optimization of other heart failure therapies 3

• For atrial fibrillation:

  • Useful for initial control of ventricular rate 3
  • Beta-blockers are usually more effective when added to digoxin for rate control, particularly during exercise 3

Management of Digoxin Toxicity in CAPD Patients

• If toxicity occurs, treatment options include:
  • Cessation of the drug 6
  • Correction of electrolyte abnormalities 6
  • Digoxin-specific Fab antibody fragments for severe toxicity 2
  • Continuous venovenous hemodialysis may be considered in cases where Fab fragments are unavailable 6