Canis ISSN: 2398-2942

Digoxin toxicity

Contributor(s): Barrett Bulmer, Craig Devine

Introduction

  • Digoxin Digoxin is currently the only positive inotrope, negative chronotrope available. Its positive inotropic actions are via inhibition of the Na+/K+ ATPase and its negative chronotropic effects are via both direct and indirect sympatholytic/parasympathomimetic actions.
  • It is utilized most often in the management of systolic dysfunction, ie dilated cardiomyopathy Heart: dilated cardiomyopathy (DCM) , and may be used in the treatment of supraventricular arrhythmias, ie atrial fibrillation Heart: atrial fibrillation.
  • The development of more potent agents such as pimobendan Pimobendan , is likely to reduce reliance on this weak positive inotrope for the support of systolic function in dogs.
  • Although controversy exists over its use in additional conditions there is little debate that inappropriate or unmonitored digoxin administration may carry significant toxicity.
  • While digoxin has been utilized in the management of canine cardiovascular disease for decades, the incidence of digoxin toxicity is poorly documented.
    • One report states that 15.3% of 222 dogs in the enalapril Enalapril clinical studies had serum digoxin concentrations greater than 3.0 ng/ml and 9.1% had signs consistent with digoxin toxicity.
    • A trend toward utilizing lower doses of digoxin and monitoring serum digoxin concentrations will likely reduce the frequency and severity of digoxin intoxication.

Potential toxicities

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Predisposing factors

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Treatment utilizing digoxin

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Recognition of digoxin toxicity

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Treatment of digoxin toxicity

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Further Reading

Publications

Refereed papers

  • Recent references from VetMedResource and PubMed.
  • Rathore S S et al (2003) Association of serum digoxin concentration and outcomes in patients with heart failure. JAMA 289(7), 871-878 PubMed.
  • Merrett D (2000) Digoxin therapy. Aust Vet J 78(9), 612-615.
  • Ward D M et al (1999) Treatment of severe chronic digoxin toxicosis in a dog with cardiac disease, using ovine digoxin-specific immunoglobulin G Fab fragments. JAVMA 215(12), 1808-1812 PubMed.
  • Synder P S & Panciera D L & Volk L (1993) Digoxin pharmacokinetics in dogs with experimental hypothyroidism. Proc Ann Vet Med Forum (Abstract).

Other sources of information

  • Opie L H, Gersh B J (2001) Drugs for the Heart. 5th edition, Philadelphia, W.B. Saunders. Chapter 6, pp 154-186.
  • Muir W W III, Sams R A, Moise N S (1999) Textbook of Canine and Feline Cardiology-Principles and Clinical Practice. 2nd edition, Philadelphia, W.B. Saunders. Chapter 17, pp 307-330.
  • Sisson D D & Kittleson M D (1999) Textbook of Canine and Feline Cardiology-Principles and Clinical Practice.2nd edition, Philadelphia, W.B. Saunders. Chapter 12, pp 216-250.
  • Kittleson M (1998) Small Animal Cardiovascular Medicine. Mosby Inc. p 165.


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