What is the recommended dose of digoxin (digitalis glycoside) for intravenous administration?

Intravenous Digoxin Dosing Guidelines

For adult patients requiring intravenous digoxin, the recommended loading dose is 8-12 mcg/kg, with half the total loading dose administered initially, followed by one-quarter of the loading dose every 6-8 hours twice. 1

Loading Dose Administration

• The total IV loading dose for adults and pediatric patients over 10 years is 8-12 mcg/kg 1
• Administration should be divided: give half the total loading dose initially, then one-quarter of the loading dose every 6-8 hours twice 1
• For a 70 kg adult, this typically translates to a total loading dose of approximately 560-840 mcg (0.56-0.84 mg) 1
• Administer the dose over a period of 5 minutes or longer and avoid bolus administration to prevent systemic and coronary vasoconstriction 1
• For adults, no more than 500 mcg (0.5 mg) of digoxin injection should be injected into a single site 1

Maintenance Dosing

• The recommended starting maintenance dose for adults and pediatric patients over 10 years with normal renal function is 2.4-3.6 mcg/kg/day given once daily 1
• Maintenance doses should be adjusted based on lean body weight, renal function, age, and concomitant medications 1
• For most adults, the maintenance dose ranges from 125-250 mcg (0.125-0.25 mg) daily 2, 3
• Lower doses (0.125 mg daily or every other day) should be used for patients over 70 years, those with impaired renal function, or those with low lean body mass 2

Renal Function Considerations

• Patients with renal dysfunction require reduced loading and maintenance doses 4
• For patients with creatinine clearance below 60 mL/min, loading doses should be reduced to 6-10 mcg/kg 4
• For patients with advanced renal failure (dialysis-dependent), an appropriate IV loading dose is approximately 10 mcg/kg 5
• The maintenance dose must be adjusted according to creatinine clearance as shown in the FDA guidelines 1

Administration Guidelines

• Parenteral administration should be used only when rapid digitalization is urgent or when oral administration is not possible 1
• Intravenous administration is preferred over intramuscular due to pain at injection sites 1
• Digoxin injection can be administered undiluted or diluted with a 4-fold or greater volume of Sterile Water for Injection, 0.9% Sodium Chloride Injection, or 5% Dextrose Injection 1
• Use of less than a 4-fold volume of diluent could lead to precipitation of the digoxin 1
• Immediate use of the diluted product is recommended 1

Monitoring

• Monitor for signs and symptoms of digoxin toxicity and clinical response 1
• Serum digoxin levels less than 0.5 ng/mL have been associated with diminished efficacy, while levels above 2 ng/mL have been associated with increased toxicity without increased benefit 1
• The therapeutic serum concentration should be maintained between 0.6 and 1.2 ng/mL 6
• Obtain serum digoxin concentrations just before the next scheduled digoxin injection dose or at least 6 hours after the last dose 1

Special Considerations

• Consider interruption or reduction in digoxin dose prior to electrical cardioversion to avoid induction of ventricular arrhythmias 1
• Digoxin is contraindicated in patients with ventricular fibrillation 1
• Use with caution in patients with pre-existing sinus node disease or incomplete AV block 1
• Signs of digoxin toxicity include anorexia, nausea, vomiting, visual changes, and cardiac arrhythmias 1

Digoxin in Specific Conditions

• For symptomatic sinus bradycardia or atrioventricular block, other medications like atropine, dopamine, isoproterenol, or epinephrine may be preferred 7
• For digoxin overdose, digoxin antibody fragment is the treatment of choice, with dosage dependent on amount ingested or known digoxin concentration 7

Remember that toxic levels of digoxin are only slightly higher than therapeutic levels, so careful dosing and monitoring are essential 1.