Name: DIGOXIN (LanoxinR)
Classification: cardiac glycoside
  • used in treatment of atrial fibrillation, atrial flutter, atrial tachycardia
  • positive inotrope, negative chronotrope, negative dromotrope
  • used to improve cardiac output in congestive heart failure
Dose:
  • for congestive heart failure:
    • loading dose: 8 - 10 mcg/kg lean body weight
    • half of total dose given as first dose and additional fractions are given at 6 to 8 hour intervals
  • maintenance dose: 
    • 1/3 of loading dose/day
  • for atrial fibrillation:
    • loading dose: 10 - 15 mcg/kg lean body weight administered as above
  • reduce dosage in renal failure, hypothyroidism
Administration: IV Direct:
  • over 2 - 3 min or ADC in 50 ml D5W or NS over 5 - 10 min
  • if diluting, dilute with four times or greater volume to avoid precipitation
  • onset of action 5 - 30 minutes post IV bolus
Adverse Effects: Symptoms of Toxicity:
  • gastrointestinal effects: anorexia, nausea, vomiting (common early signs of toxicity)
  • CNS effects: headache, fatigue, drowsiness, generalized muscle weaknessoccular effects: 'yellow and green' halo vision
Effects on potassium:
  • chronic toxicity: hypokalemia 
  • acute toxicity: hyperkalemia
Cardiac effects:
  • every kind of arrhythmia, AV block (PAT with block, atrial fibrillation with complete heart block very suggestive of digoxin toxicity)
  • risk factors:
    • potassium/magnesium deficiencies or hypercalcemia increase risk of toxicity
    • febrile or hypermetabolism-induced atrial arrhythmias may be resistant to digoxin, predisposing to toxicity
Drug Interactions:
  • beta blockers + digoxin = increased digoxin toxicity, decreased inotropic effect
  • calcium + digoxin = increased risk of arrhythmias
  • verapamil + digoxin = increased digoxin level
  • propafenone + digoxin = decreased inotropic effect
  • quinidine + digoxin = increased digoxin level
  • rifampin + digoxin = decreased digoxin level
  • sympathomimetics + digoxin = increased risk of arrhythmias
  • drugs which cause hypokalemia = increased risk of digoxin toxicity
Monitoring Therapy:
  • heart rate
  • PR interval
  • ECG
  • potassium, magnesium and calcium levels
  • BUN, creatinine
  • cardiac indices
  • routine levels not indicated; dosage adjustments should be based on symptomatology
CCTC Protocol:
  • May be administered by intermittent IV infusion by an RN.
  • May be given IV direct by an approved nurse in the CCTC.


Lynne Kelly, Pharmacist, CCTC
Brenda Morgan, Clinical Nurse Specialist, CCTC
Last Update: August 7, 2006

LHSCHealth Professionals

Last Updated March 24, 2009 | © 2007, LHSC, London Ontario Canada