Digoxin

Original article by Tom Leach | Last updated on 16/5/2014
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Introduction

Digoxin is a cardiac glycoside, which have two main effects:
  • Increases the force of contractions (through increased intracellular Ca2+​)
  • Reduce conduction through the AV node
 
It is most commonly used to control AF and atrial flutter, and in some cases, digoxin may also be used in heart failure.
 

Digoxin in Atrial fibrillation

  • Not the first line treatment in an variety of AF. Particularly in acute cases, it takes too long to act, and tachycardia may still persist even after the maximum dose.
  • See the AF article for more details
 

Digoxin Toxicty

Results from increased digoxin levels in the blood

  • Can be particularly difficult to identify as it is often similar to patient deterioration due to underlying disease
  • Is more likely in elderly patients

May occur in renal failure – as the drug is excreted by the kidneys

Symptoms

  • Xanthopsia – a yellow ring / discolouration of the vision
  • Bradycardias
  • Ventricular ectopic beats
  • Heart block (various types)
  • VT/VF – rare

Investigations

  • Always check potassium! Hypokalaemia predisposes to cardiac side effects of digoxin, even when the levels of digoxin are low / therapeutic