At what pulse rate should digoxin (digitalis glycoside) be withheld?

When to Withhold Digoxin Based on Pulse Rate

Digoxin should be withheld when the pulse rate is less than 60 beats per minute or if there is significant sinus or atrioventricular block. 1

General Guidelines for Withholding Digoxin

• Digoxin should not be administered to patients with significant sinus or atrioventricular block, unless the block has been addressed with a permanent pacemaker 1
• Withhold digoxin when heart rate falls below 60 beats per minute, as bradycardia is a common manifestation of digoxin toxicity 2
• Digoxin should be used cautiously in patients taking other drugs that can depress sinus or atrioventricular nodal function (e.g., amiodarone or beta-blockers) 1
• Temporarily suspend digoxin during intercurrent illness, planned IV radiocontrast administration, bowel preparation prior to colonoscopy, or prior to major surgery 1

Risk Factors for Digoxin Toxicity

• Overt digoxin toxicity is commonly associated with serum digoxin levels greater than 2 ng/mL 1, 2
• Toxicity may occur with lower digoxin levels if any of these conditions exist:
  • Hypokalemia 1, 2
  • Hypomagnesemia 1, 2
  • Hypothyroidism 1, 2
• Concomitant use of medications that increase serum digoxin concentrations:
  • Amiodarone (reduce digoxin dose by 30-50%) 3, 4
  • Clarithromycin, erythromycin 1, 2
  • Verapamil, quinidine 1, 2
  • Itraconazole, cyclosporine 1, 2

Monitoring Parameters

• Regular monitoring of heart rate and rhythm is essential when using digoxin 1
• Target serum digoxin concentration should be maintained between 0.5-0.9 ng/mL 1, 4
• Higher serum concentrations (>1.0 ng/mL) have not shown superior outcomes and may increase mortality risk 1, 4
• Monitor serum electrolytes (potassium, magnesium) and renal function regularly 4, 2

Signs of Digoxin Toxicity

• Cardiac manifestations:
  • Bradycardia (heart rate <60 beats per minute) 2
  • Enhanced atrial, junctional, or ventricular automaticity 2
  • Atrioventricular block 2
  • Ventricular tachycardia (particularly fascicular or bidirectional) 2
• Non-cardiac manifestations:
  • Gastrointestinal symptoms (anorexia, nausea, vomiting) 1, 2
  • Neurological symptoms (visual disturbances, confusion, disorientation) 1, 2

Special Considerations for Elderly Patients

• Low doses (0.125 mg daily or every other day) should be used initially if the patient is more than 70 years old 1, 4
• Elderly patients are at increased risk of digoxin toxicity due to:
  • Reduced renal function 1, 4, 5
  • Low lean body mass 1, 4
• Consider withholding digoxin at higher heart rates (e.g., <65-70 beats per minute) in elderly patients 5

Management When Digoxin Must Be Resumed

• If digoxin therapy must be continued after withholding due to bradycardia:
  • Use lower doses (0.125 mg daily or every other day) 4, 2
  • Avoid loading doses 2
  • Monitor heart rate and digoxin levels more frequently 4, 2
• Consider alternative rate control agents for atrial fibrillation if appropriate 1, 6