Liverpool Hospital Emergency Department

 Indications for use: 

  • Acute digoxin overdose
    • Cardiac arrest presumed due to digoxin
    • Hyperkalaemia >5.5mmol/L with digoxin ingestion
    • Life-threatening ventricular arrhythmias or runs of ventricular ectopics 
    • Decompensation with bradycardia
    • Dig level (predigifab) >15nmol/L (>12ng/ml) and toxicity 
  • Chronic digoxin toxicity
    • Cardiac arrest
    • Ventricular arrythmias and runs of ectopics
    • Bradyarrhythmia with hypotension 
  • Cardiac Glycoside overdose:
    • Foxglove
    • Oleander 

Formulation: (Sterile Powder in Fridge) 

Digoxin binding Antibody fragments (Fab) 

  • 1 vial = 40mg Digifab -> binds 0.5mg Digoxin
  • Reconstitute each vial with 4ml sterile water for injection
  • Dilute up to 100ml 0.9% Normal Saline
  • Infusion over 15-30mins as below, with 0.22micron filter 

Dosage and Administration 

  • ACUTE POISONING – If no response, discuss with Toxicologist
    • Cardiac Arrest:
      • X5 Digifab vials (200mg) as a rapid injection (5-10 minutely) (20 vials)
    • NOT in Cardiac Arrest:
      • Titrate to effect giving x2 vials initially over 15-30 minutes
      • Partial response – repeat after 30 minutes 

Monitor for 12 hours post 

  • Digoxin may be mobilised from tissues leading to further toxicity requiring and require an additional 1-2 vials 

  • CHRONIC POISONING – If no response, discuss with Toxicologist
    • Cardiac Arrest:
      • Follow ALS / Treat hyperkalaemia and use 2 vials of Digifab
    • NOT in Cardiac Arrest:
      • 1 vial and assess response 

Monitor until cardiac effects resolve. Second dosing may be needed 

Side Effects 

  • Poor cardiac baseline function (CCF) may worsen due to withdrawal of digoxin’s inotropic support
  • If BG of AF may develop -> AF + RVR due to removal of digoxin AV Blockade
  • Rapid Hypokalaemia (from reactivation of Na/K ATPase)
  • Hypersensitivity (relative contraindication, very rare) 

Pit Falls 

  • Treat Bradyarrhythmia with Atropine initially
  • Prompt Electrolyte correction is key
  • Hypokalaemia worsens Digoxin toxicity – Rapid correction required 
  • Note Digifab will lead to further hypokalaemia initially
  • Hypomagnesaemia worsens digoxin toxicity – Rapid correction
  • Hyperkalaemia
  • Treat HyperK with IV Bicarb + Insulin/Dex + Digifab
  • Calcium can be considered with evidence of ECG changes.
    • The risk of the stone heart theory is overstated
  • K>5.5 from Digoxin toxicity is 100% fatal if not treated 

NB – Digifab Binding Digoxin -> increased total serum digoxin concentrations (however free digoxin  concentrations are reduced).