Romifidine is an alpha-2 adrenergic agonist used for sedation and analgesia in horses. As it is a prohibited substance, its purported use at low doses in performance horses necessitates further study. The primary goal of the study reported here was to describe the serum concentrations and pharmacokinetics of romifidine following low-dose administration immediately prior to exercise, utilizing a highly sensitive liquid chromatography–tandem mass spectrometry assay that is currently employed in many drug testing laboratories. An additional objective was to describe changes in heart rate and rhythm following intravenous administration of romifidine followed by exercise. Eight adult Quarter Horses received a single intravenous dose of 5 mg (0.01 mg/kg) romifidine followed by 1 h of exercise. Blood samples were collected and drug concentrations measured at time 0 and at various times up to 72 h. Mean ± SD systemic clearance, steady-state volume of distribution and terminal elimination half-life were 34.1 ± 6.06 mL/min/kg and 4.89 ± 1.31 L/kg and 3.09 ± 1.18 h, respectively. Romifidine serum concentrations fell below the LOQ (0.01 ng/mL) and the LOD (0.005 ng/mL) by 24 h postadministration. Heart rate and rhythm appeared unaffected when a low dose of romifidine was administered immediately prior to exercise.
|Number of pages||6|
|Journal||Journal of Veterinary Pharmacology and Therapeutics|
|State||Published - Oct 2017|
Bibliographical noteFunding Information:
Financial support for this project was provided by the National Cutting Horse Association, National Reining Horse Association and the California Department of Food and Agriculture’s Equine Medication Monitoring Program. The authors would like to thank Alexandria White, Kelsey Seminoff, Sandy Yim and Alexa Johnson for technical support.
© 2017 John Wiley & Sons Ltd
Copyright 2018 Elsevier B.V., All rights reserved.
ASJC Scopus subject areas
- Veterinary (all)