Toxicity in Doberman Pinchers with Ventricular Arrhythmias Treated with Amiodarone (1996–2005)

Abstract

Background: Asymptomatic Doberman Pinschers with dilated cardiomyopathy (DCM) often die suddenly owing to ventricular tachycardia that degenerates into ventricular fibrillation. A safe and effective antiarrhythmic drug treatment is needed. This will require a large, well-controlled, prospective study.Hypothesis: Amiodarone toxicity is common in Dobermans with occult DCM and ventricular tachyarrhythmias refractory to antiarrhythmia therapy. Infrequent monitoring of hepatic function is inadequate. Frequent monitoring may be useful to determine dogs in which the dosage should be decreased or the drug withdrawn.Methods: Medical records from the University of Georgia and Cornell University were searched for Doberman Pinschers diagnosed with preclinical DCM that received amiodarone for severe ventricular arrhythmias refractory to other antiarrhythmic agents. Echocardiographic data, Holter recording data, hepatic enzyme serum activity, and serum amiodarone concentrations were recorded. The presence of clinical signs of toxicity was recorded. Serum amiodarone concentrations were obtained in some dogs.Results: Reversible toxicity was identified in 10 of 22 (45%) dogs. Conclusion and Clinical Importance: Adverse effects from amiodarone were common and were, in part, dosage related. Patients should be monitored for signs of toxicity and liver enzyme activity should be measured at least monthly.

Ability of a 5-Minute Electrocardiography (ECG) for Predicting Arrhythmias in Doberman Pinschers with Cardiomyopathy in Comparison with a 24-Hour Ambulatory ECG

“…3,7,8,16,17 Because of the high frequency of electrical abnormalities in this breed, Holter examination was suggested to be the best test for detecting early changes, 3,7,17 and thus Holter examinations have been evaluated and recommended in Doberman Pinschers as well as in other breeds for the purpose of diagnostic and therapeutic considerations. 3,7,17,[19][20][21][22][23][24][25] However, availability of Holter recorders and expense of this technique may preclude its use in many dogs. 18,26 Consequently, many veterinarians currently base diagnostic and therapeutic decisions on lead II ECGs performed for only a brief period, while the dog is in the hospital.…”

Effects of an adapted intravenous amiodarone treatment protocol in horses with atrial fibrillation

“…AD administration have been described (Agozzino et al 2002;Fransi and Briedis 2004;Bravo et al 2005). Also, in dogs, adverse effects due to chronic AD treatment include hepatopathy, anorexia, lethargy, pruritis, neutropenia and thrombocytopenia Gilbert et al 2000;Kraus et al 2005;Oyama and Prosek 2006). In a previous equine AD study, adverse clinical signs included an increase of total bilirubin and weakness of the hindlimb (De Clercq et al 2006a).…”

ACVIM consensus statement on the diagnosis and treatment of chronic hepatitis in dogs

“…In the case of phenobarbital, toxicity may be direct or related to altered metabolism of other xenobiotics. Several other drugs or toxins including carprofen, oxidbendazole, amiodarone, aflatoxin, and cycasin may lead to CH although they more commonly cause acute hepatic injury . In humans, it is estimated that herbal and dietary supplements are responsible for up to 18% of drug‐induced liver injury (refer to https://livertox.nih.gov/).…”