Antidote: digoxin immune Fab
Introduction
Digoxin-specific immune antibody fragments (digoxin immune Fab) bind digoxin in the circulation and remove it from its site of action, the sodium-potassium adenosine triphosphatase (ATPase) pump. One vial of digoxin immune Fab contains 40 mg of antibody fragments that bind approximately 0.5 mg of digoxin1.
In chronic accumulation of digoxin, digoxin immune Fab is indicated for:
- cardiac arrest
- ventricular arrhythmias or runs of ventricular ectopic complexes
- bradyarrhythmias with hypotension.
The dose of digoxin immune Fab depends on whether or not the patient is in cardiac arrest—see Patient not in cardiac arrest and Patient in cardiac arrest.
Patient not in cardiac arrest
For an adult or child with chronic digoxin accumulation who is not in cardiac arrest, but has life-threatening arrhythmias (ventricular arrhythmias, runs of ventricular ectopic complexes, or bradyarrhythmias with hypotension), use:
digoxin immune Fab 40 mg (1 vial) intravenously, over 30 minutes2. If there is no response, seek advice from a clinical toxicologist. chronic digoxin accumulation
Monitor the patient until cardiac effects resolve. This is particularly important in chronic digoxin accumulation. Digoxin immune Fab is eliminated in 12 to 24 hours, whereas digoxin is slowly mobilised from the tissues. If toxic effects recur, for an adult or child, use:
digoxin immune Fab 40 mg (1 vial) intravenously, over 30 minutes2.
Patient in cardiac arrest
If an adult or child with chronic digoxin accumulation is in cardiac arrest:
- follow advanced life support protocols3
- treat hyperkalaemia if present
- use digoxin immune Fab.
For an adult or child in cardiac arrest, use:
digoxin immune Fab 80 mg (2 vials) intravenously, as a rapid injection4. If there is no response, seek advice from a clinical toxicologist.