Clinical presentation

Effects of acute digoxin poisoning can take up to 6 hours to occur after ingestion because the drug is being distributed into the myocardium and other tissues.

Effects of acute digoxin poisoning include:

• cardiovascular effects
  • minor or early electrocardiographic changes—ST depression with the characteristic ‘reverse tick’ appearance, ectopic beats, first-degree atrioventricular (AV) nodal block
  • bradyarrhythmias—slow atrial fibrillation, second- and third-degree AV block
  • junctional and atrial tachycardia
  • hypotension, syncope
  • ventricular tachycardia, cardiac arrest (ventricular fibrillation, asystole)
  • gastrointestinal effects—nausea, vomiting, abdominal pain, diarrhoea
• metabolic effects—severe digoxin poisoning causes hyperkalaemia with associated electrocardiographic changes; pre-existing hypokalaemia and hypomagnesaemia can exacerbate digoxin toxicity
• central nervous system effects—lethargy, confusion, delirium.