From the Guidelines
Digoxin overdose requires immediate medical attention, and the primary treatment approach is administration of Digoxin Immune Fab (Digibind or DigiFab), which binds to digoxin molecules and removes them from circulation, as recommended by the 2023 American Heart Association guidelines 1.
Symptoms of Digoxin Overdose
The symptoms of digoxin overdose include:
- Enhanced atrial, junctional, or ventricular automaticity (with ectopic beats or tachycardia) often combined with atrioventricular block
- Ventricular tachycardia (VT) that is fascicular or bidirectional in origin
- Severe digoxin overdose causes hyperkalemia and cardiac standstill
- Visual disturbances, nausea, changes in mentation
- Elevated serum concentrations
Treatment of Digoxin Overdose
The treatment of digoxin toxicity is based on the severity, and the following approaches are recommended:
- Discontinuing the medication, monitoring rhythm, and maintaining normal serum potassium may be sufficient for mild cases
- Intravenous magnesium is often administered if ventricular arrhythmias (VAs) are present
- Temporary pacing may be needed for atrioventricular block or asystole
- For more severe intoxication (serum digoxin concentrations exceeding 4 ng/mL and with serious arrhythmias such as VT), the treatment of choice is digoxin-specific Fab antibody
- Doses lower (and less expensive) than the full neutralizing dose are sufficient as long as cardiac arrest is not imminent
- Hyperkalemia, a common complication, may require insulin with glucose, sodium bicarbonate, or calcium if life-threatening
- Bradyarrhythmias might need temporary pacing, while ventricular arrhythmias may require lidocaine or phenytoin
- Avoid calcium channel blockers and beta-blockers as they can worsen cardiac conduction issues
- Hemodialysis is ineffective for digoxin removal due to its large volume of distribution, as stated in the 2023 American Heart Association guidelines 1.
Key Considerations
- Potentiating factors may include hypothyroidism, hypokalemia, or renal dysfunction
- Monitoring high-risk patients during initiation of QT-prolonging antiarrhythmic medications and recognition of the syndrome when it occurs are the first steps
- Digoxin concentration monitoring is unreliable after antidigoxin antibody administration
- Adverse effects of digoxin-specific Fab antibody include worsening of the underlying disease (increased ventricular rate during AF, exacerbation of HF) and hypokalemia, as noted in the 2018 ACC/AHA/HRS guideline on the evaluation and management of patients with bradycardia and cardiac conduction delay 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. Manifestations of life-threatening toxicity include ventricular tachycardia or ventricular fibrillation, or progressive bradyarrhythmias, or heart block Massive Digitalis Overdosage: DIGIBIND should be used to reverse the toxic effects of ingestion of a massive overdose
The symptoms of Digoxin overdose include:
- Ventricular arrhythmias
- Symptomatic bradyarrhythmia or heart block
- Progressive bradyarrhythmias
- Ventricular tachycardia or ventricular fibrillation
- Life-threatening hyperkalemia
The treatment of Digoxin overdose includes:
- Withdrawal of digoxin
- Reversal of toxicity with DIGIBIND (Digoxin Immune Fab)
- Correction of electrolyte disorders (e.g. hypokalemia, hypomagnesemia)
- Administration of atropine or insertion of a temporary cardiac pacemaker for symptomatic bradyarrhythmia or heart block
- Administration of activated charcoal to prevent absorption and bind digoxin in the gut during enteroenteric recirculation 2
From the Research
Symptoms of Digoxin Overdose
- Anorexia, nausea, vomiting, and neurological symptoms 3
- Fatal arrhythmias, including ventricular tachycardia and fibrillation 3, 4
- Haemodynamic instability and hyperkalaemia (> 6 mmol/L) 5, 4
- Tachy-bradyarrhythmias 5
Treatment of Digoxin Overdose
- Digoxin-specific antibody fragments (digoxin-Fab) are a safe and effective treatment for acute and chronic digoxin poisoning 5, 3, 6, 7
- Indications for digoxin-Fab include life-threatening tachy-bradyarrhythmias, hyperkalaemia (> 6 mmol/L), and haemodynamic instability with an elevated digoxin concentration (> 2 μg/L or 2.6 nmol/L) 5
- Dosage of digoxin-Fab:
- 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 5
- In chronic poisoning, 40 mg (1 vial) digoxin-Fab at a time, repeated after 60 min if patient is still symptomatic, is suggested 5
- Amiodarone may be used to treat ventricular arrhythmias in severe digoxin poisoning, followed by pacing if necessary, and Fab antibody fragments if hyperkalaemia persists 4
- Monitoring should continue after treatment due to the small risk of rebound toxicity 3