Abstract
Objectives
To evaluate the sedative effects and pharmacokinetics of detomidine gel administered
intravaginally to alpacas in comparison with intravenously (IV) administered detomidine.
Study design
Randomized, crossover, blinded experiment.
Animals
A group of six healthy adult female Huacaya alpacas (70.3 ± 7.9 kg).
Methods
Alpacas were studied on two occasions separated by ≥5 days. Treatments were IV detomidine
hydrochloride (70 μg kg−1; treatment DET–IV) or detomidine gel (200 μg kg−1; treatment DET–VAG) administered intravaginally. Sedation and heart rate (HR) were
evaluated at intervals for 240 minutes. Venous blood was collected at intervals for
360 minutes after treatment for analysis of detomidine, carboxydetomidine and hydroxydetomidine
using liquid chromatography–tandem mass spectrometry. Measured variables were compared
between treatments and over time using mixed model analysis. Data are presented as
the mean ± standard error of the mean, and a p value of <0.05 was considered significant.
Results
Onset of sedation was faster in treatment DET–IV (1.6 ± 0.2 minutes) than in treatment
DET–VAG (13.0 ± 2.5 minutes). Time to maximum sedation was shorter in treatment DET–IV
(8.3 ± 1.3 minutes) than in treatment DET–VAG (25 ± 4 minutes). Duration of sedation
was not different between treatments. There was a significant linear relationship
between sedation score and plasma detomidine concentration. HR was less than baseline
for 60 and 125 minutes for treatments DET–IV and DET–VAG, respectively. The maximal
decrease in HR occurred at 15 minutes for both treatments. The mean maximum plasma
concentration of detomidine, time to maximum concentration and bioavailability for
treatment DET–VAG were 39.6 ng mL−1, 19.9 minutes and 20%, respectively.
Conclusions and clinical relevance
Detomidine administration at the doses studied resulted in moderate sedation when
administered IV or intravaginally to alpacas.
Keywords
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Article info
Publication history
Published online: July 26, 2020
Accepted:
July 8,
2020
Received:
February 24,
2020
Identification
Copyright
© 2020 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.
