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

Abstract

REASON FOR PERFORMING STUDY:

Good results have been obtained with a human amiodarone (AD) i.v. protocol in horses with chronic atrial fibrillation (AF) and a pharmacokinetic study is required for a specific i.v. amiodarone treatment protocol for horses.

OBJECTIVES:

To study the efficacy of this pharmacokinetic based i.v. AD protocol in horses with chronic AF.

METHODS:

Six horses with chronic AF were treated with an adapted AD infusion protocol. The protocol consisted of 2 phases with a loading dose followed by a maintenance infusion. In the first phase, horses received an infusion of 6.52 mg AD/kg bwt/h for 1 h followed by 1.1 mg/kg bwt/h for 47 h. In the second phase, horses received a second loading dose of 3.74 mg AD/kg bwt/h for 1 h followed by 1.31 mg/kg bwt/h for 47 h. Clinical signs were monitored, a surface ECG and an intra-atrial electrogram were recorded. AD treatment was discontinued when conversion or any side effects were observed.

RESULTS:

Three of the 6 horses cardioverted successfully without side effects. The other 3 horses did not convert and showed adverse effects, including diarrhoea. In the latter, there were no important circulatory problems, but the diarrhoea continued for 10-14 days. The third horse had to be subjected to euthanasia because a concomitant Salmonella infection worsened the clinical signs.

CONCLUSION:

The applied treatment protocol based upon pharmacokinetic data achieved clinically relevant concentrations of AD and desethylamiodarone.

POTENTIAL RELEVANCE:

Intravenous AD has the potential to be an alternative pharmacological treatment for AF in horses, although AD may lead to adverse drug effects, particularly with cumulative dosing.

• Authors: D De Clercq, G van Loon, K Baert, R Tavernier, S Croubels, P De Backer, P Deprez
• Journal: Equine veterinary journal (Equine Vet J) Vol. 39 Issue 4 Pg. 344-9 (Jul 2007) ISSN: 0425-1644 [Print] United States
• PMID: 17722727 (Publication Type: Journal Article)

Chemical References

• Anti-Arrhythmia Agents
• Amiodarone

Topics

• Amiodarone (administration & dosage, adverse effects, pharmacokinetics)
• Animals
• Anti-Arrhythmia Agents (administration & dosage, adverse effects, pharmacokinetics)
• Atrial Fibrillation (drug therapy, veterinary)
• Diarrhea (chemically induced, veterinary)
• Dose-Response Relationship, Drug
• Echocardiography (veterinary)
• Echocardiography, Doppler, Color (veterinary)
• Horse Diseases (drug therapy)
• Horses
• Infusions, Intravenous (veterinary)
• Treatment Outcome