What is the management for digoxin toxicity?

From the Guidelines

Management of digoxin toxicity begins with discontinuation of digoxin and close cardiac monitoring, with digoxin-specific antibody fragments (Digibind or DigiFab) being the primary treatment for severe toxicity, as recommended by the 2023 American Heart Association guidelines 1.

Key Considerations

• Discontinuation of digoxin and close cardiac monitoring are essential for managing digoxin toxicity.
• For mild toxicity with stable vital signs, supportive care may be sufficient, including correction of electrolyte abnormalities, particularly hyperkalemia, which may require insulin with glucose, sodium bicarbonate, or calcium if life-threatening 1.
• For severe toxicity, digoxin-specific antibody fragments (Digibind or DigiFab) are the primary treatment, with a common dosing approach being 40-80 mg for acute overdose or 10-20 mg for chronic toxicity 1.
• Arrhythmias may need treatment with phenytoin, lidocaine, or magnesium sulfate, while avoiding calcium channel blockers and beta-blockers which can worsen heart block 1.
• Hemodialysis is ineffective for removing digoxin but may help manage renal failure or severe electrolyte disturbances 1.
• Activated charcoal (50-100g) can be administered within 1-2 hours of acute ingestion to reduce absorption 1.

Treatment Approach

• The treatment approach should be based on the severity of the toxicity, with mild cases requiring supportive care and severe cases requiring digoxin-specific antibody fragments.
• The dosage of digoxin-specific antibody fragments should be based on the amount of digoxin ingested or serum levels, with repeat dosing may be necessary, particularly in the setting of chronic use attributable to the large volume of distribution 1.
• Clinical response rates to digoxin Fab are as high as 80% to 90%, particularly in the acute setting, and patients with hyperkalemia or arrhythmias in the setting of digoxin serum levels of >2 mcg/L are at increased risk of death 1.

From the FDA Drug Label

OVERDOSAGE Digoxin should be temporarily discontinued until the adverse reaction resolves. Every effort should also be made to correct factors that may contribute to the adverse reaction (such as electrolyte disturbances or concurrent medications). Treatment of Adverse Reactions Produced by Overdosage: Withdrawal of digoxin may be all that is required to treat the adverse reaction. However, when the primary manifestation of digoxin overdosage is a cardiac arrhythmia, additional therapy may be needed If the rhythm disturbance is a symptomatic bradyarrhythmia or heart block, consideration should be given to the reversal of toxicity with DIGIBIND® [Digoxin Immune Fab (Ovine)] (see Massive Digitalis Overdosage subsection), the use of atropine, or the insertion of a temporary cardiac pacemaker If the rhythm disturbance is a ventricular arrhythmia, consideration should be given to the correction of electrolyte disorders, particularly if hypokalemia (see Administration of Potassium subsection) or hypomagnesemia is present DIGIBIND is a specific antidote for digoxin and may be used to reverse potentially life-threatening ventricular arrhythmias due to digoxin overdosage.

The management for digoxin toxicity includes:

• Temporary discontinuation of digoxin until the adverse reaction resolves
• Correction of contributing factors such as electrolyte disturbances or concurrent medications
• Withdrawal of digoxin as the primary treatment for adverse reactions
• Additional therapy for cardiac arrhythmias, including:
  • Reversal of toxicity with DIGIBIND for symptomatic bradyarrhythmia or heart block
  • Atropine for symptomatic bradyarrhythmia or heart block
  • Temporary cardiac pacemaker for symptomatic bradyarrhythmia or heart block
  • Correction of electrolyte disorders for ventricular arrhythmias, particularly hypokalemia or hypomagnesemia
• Administration of potassium to maintain serum potassium concentration between 4.0 and 5.5 mmol/L, usually orally but cautiously by intravenous route in urgent cases 2

From the Research

Management of Digoxin Toxicity

The management of digoxin toxicity involves several strategies, including the use of digoxin-specific antibody fragments (Fab), magnesium sulfate, and supportive care.

• The use of digoxin-specific antibody fragments (Fab) is widely regarded as a safe and effective treatment for the management of acute and chronic digoxin poisoning 3.
• Magnesium sulfate can also be effective in treating ventricular arrhythmias due to digoxin toxicity, especially in patients with low serum magnesium levels 4.
• Supportive care, including stomach lavage, administration of laxatives, correction of cardiac arrhythmias, provision of myocardial nutrition, diuresis, and management of electrolyte disturbances, can also be beneficial in managing digoxin toxicity 5.

Indications for Digoxin-Specific Antibody Fragments (Fab)

The indications for digoxin-specific antibody fragments (Fab) include:

• Life-threatening tachy-bradyarrhythmias
• Hyperkalaemia (> 6 mmol/L)
• Haemodynamic instability with an elevated digoxin concentration (> 2 μg/L or 2.6 nmol/L) 3
• High-grade atrioventricular conduction disorders (grade 2 and 3 A-V block), multifocal ectopic beats, ventricular tachycardia, and relapsing ventricular fibrillation 6

Dosage of Digoxin-Specific Antibody Fragments (Fab)

The dosage of digoxin-specific antibody fragments (Fab) can vary depending on the severity of the toxicity and the patient's clinical parameters.

• In acute poisoning, a small bolus of 80 mg, repeated if necessary, titrated against clinical effect, is likely to achieve equivalent benefits with much lower total doses 3.
• In chronic poisoning, it may be simplest to give 40 mg (1 vial) digoxin-Fab at a time and repeat after 60 min if there is no response 3.
• The majority of patients received 480mg of Fab in one study, with regression of arrhythmias seen between 0.5 and 8 hours after Fab infusion 6.

Supportive Care

Supportive care is crucial in managing digoxin toxicity, including:

• Stomach lavage
• Administration of laxatives
• Correction of cardiac arrhythmias
• Provision of myocardial nutrition
• Diuresis
• Management of electrolyte disturbances 5
• Temporary pacemaker therapy for patients presenting with high atrioventricular block
• Hemoperfusion for patients with renal insufficiency to eliminate digoxin from the body 5