Evaluation of the pharmacokinetics and bioavailability of intravenously and orally administered amiodarone in horses

Abstract

Results indicate that the pharmacokinetic distribution of amiodarone is multicompartmental. This information is useful for determining treatment regimens for horses with arrythmias. Amiodarone has low bioavailability after oral administration, does not undergo renal excretion, and is highly protein-bound in horses.

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

“…of 2.5 ± 1.3 Vardas et al 2000). Based upon this information, the results from a pharmacokinetic study were used to calculate the infusion protocol for horses (De Clercq et al 2006b). After 24 h, the mean AD plasma level was 2.01 ± 0.33 µg/ml (n = 6).…”

“…Based on the results of a previous study, where a steady state concentration of 1.0 µg/ml was found (De Clercq et al 2006a) and the literature concerning the therapeutic window of amiodarone ), a decision was made to aim for a steady state of 2.0 µg/ml of AD in a first phase of 2 days and a steady state of 2.5 µg/ml of AD in the second phase of 2 days. This adjustment was based on the pharmacokinetic parameters that were found after a bolus administration of 5 mg/kg bwt (De Clercq et al 2006b) in test horses. The parameters used were obtained after analysis of a 2 compartment model until the 24 h point.…”

Determination of amiodarone and desethylamiodarone in horse plasma and urine by high-performance liquid chromatography combined with UV detection and electrospray ionization mass spectrometry

“…The above methods for the quantitation of amiodarone and desethylamiodarone in horse plasma were used in two pharmacokinetic studies [13,14]. One study used the fast UV method for quantification of 'high' level samples after intravenous (IV) infusion and the other study used the sensitive LC-MS method for quantification of 'low' level samples after IV bolus administration.…”

“…The plasma and urine samples for the LC-MS/MS method originated from a single dose pharmacokinetic study of amiodarone in horses [14].…”

Pharmacokinetics and electrophysiological effects of sotalol hydrochloride in horses

“…In addition to treating the underlying disease, long-term anti-arrhythmic therapy may be indicated but few antiarrhythmic drugs are available for long-term use in horses because of low oral bioavailability, important side effects, high costs and a lack of knowledge and data supporting their use [1][2][3]. While physiological arrhythmias are mostly caused by high vagal tone, pathological arrhythmias can be associated with a wide range of both cardiac and noncardiac diseases.…”