see also: digoxin, pharmacology main index, cardiac arrhythmias

ref: EMedicine article on digitalis toxicity

• bradycardia alone ⇒ 10% if serum digoxin 1.9nmol/L & 50% if serum digoxin 3.2nmol/L
• GI symptoms alone ⇒ 25% if serum digoxin 1.9nmol/L & 60% if serum digoxin 3.2nmol/L
• GI symptoms + bradycardia ⇒ 60% if serum digoxin 1.9nmol/L & 90% if serum digoxin 3.2nmol/L
• automaticity alone ⇒ 70% if serum digoxin 1.9nmol/L & 90% if serum digoxin 3.2nmol/L
• automaticity plus bradycardia or GI symptoms ⇒ >80% if serum digoxin 1.9nmol/L & 100% if serum digoxin 3.2nmol/L
• NB. 1.9nmol/L = 1.5ng/ml; 3.2nmol/L = 2.5ng/ml;
• NB. normal Rx range 6hrs or more after last dose: 0.6-1.3nmol/L = 0.5-1.0ng/ml

• dysrhythmias associated with hemodynamic instability.
• altered mental status attributed to digoxin toxicity.
• hyperkalaemia with K+ greater than 5 mEq/L.
• serum digoxin level greater than 10 ng/mL in adults at steady state (ie, 6-8 h post acute ingestion or at baseline in the clinical setting of chronic toxicity).
• ingestion greater than 10 mg in adults (40 X 0.25 mg tablets) or greater than 0.3 mg/kg in children.

• see also Broad Complex Tachycardias and the DDx
• iv Digibind
  • whilst waiting for Digibind, iv magnesium sulphate may be life saving if VT/VF present - give 2g bolus then 1-2g/hr and check serum levels of Mg every 2hours aiming for Rx range of 4-5mEq/L.
• treat hyperkalaemia if K+ > 5.5mEq/L
  • do not give calcium to Rx hyperkalaemia as VT/VF may be precipitated
  • sodium bicarbonate 100mEq iv (1mEq/kg in children)
  • insulin 10units + 50ml 50% dextrose simultaneously as an iv bolus (0.1units/kg insulin + 0.5g/kg dextrose in children)
• treat atrioventricular block:
  • atropine 0.6mg iv bolus & rpt prn up to 1.8mg (use 20mcg/kg/dose in children)
• iv lignocaine 100mg boluses, if successful then maintenance infusion 1-4mg/min
• or iv phenytoin 100mg boluses every 5-10min up to load dose of 15mg/kg
• avoid procainamide and bretylium
• avoid DC reversion as may precipitate asystole or VF
• do not give calcium channel blockers such as verapamil (Isoptin) as they may increase digoxin toxicity
• short-acting beta blockers such as esmolol may be helpful, but may precipitate advanced or complete AV block
• ref: EMedicine article on digitalis toxicity

• standard drug measures are futile
• initiate CPR as per usual while 5 ampoules Digibind are sourced and administered iv - this may be life saving!
• continue CPR for at least 30min after administration of Digibind before considering termination of CPR as being futile.