Digoxin for atrial fibrillation: good, but not too good: a case report

Digoxin is a cardiotonic glycoside that is traditionally used for the treatment of heart failure and atrial fibrillation in humans and animals. However, the use of digoxin is still a challenge in clinical practice due to its narrow therapeutic range and its potential interaction with several drugs, which could facilitate the development of toxicity. A 12-year-old Labrador retriever was referred with a clinical diagnosis of heart failure and atrial fibrillation, anorexia, vomiting, and diarrhea. He had been medicated with digoxin, furosemide, lisinopril, and amiodarone. The patient also showed clinical signs of hip osteoarthritis and received firocoxib for four days. He additionally received drugs for gastrointeritis. The electrocardiogram demonstrated atrial fibrillation and signs of digitalis toxicity. Laboratory examination showed a high concentration of plasma digoxin, and 5 days after withdrawal of the drugs, the symptoms disappeared, as did the digitalis effects seen in the previous electrocardiogram.