Effect of yohimbine on detomidine induced changes in behavior, cardiac and blood parameters in the horse
Article first published online: 5 OCT 2012
© 2012 The Authors. Veterinary Anaesthesia and Analgesia. © 2012 Association of Veterinary Anaesthetists and the American College of Veterinary Anesthesiologists
Veterinary Anaesthesia and Analgesia
Volume 39, Issue 6, pages 574–583, November 2012
How to Cite
DiMaio Knych, H. K., Covarrubias, V. and Steffey, E. P. (2012), Effect of yohimbine on detomidine induced changes in behavior, cardiac and blood parameters in the horse. Veterinary Anaesthesia and Analgesia, 39: 574–583. doi: 10.1111/j.1467-2995.2012.00776.x
- Issue published online: 5 OCT 2012
- Article first published online: 5 OCT 2012
- Received 11 December 2010; accepted 26 August 2011.
- alpha-2 adrenergic agonist;
- cardiac arrhythmias;
Objective To describe selected pharmacodynamic effects of detomidine and yohimbine when administered alone and in sequence.
Study design Randomized crossover design.
Animals Nine healthy adult horses aged 9 ± 4 years and weighing 561 ± 56 kg.
Methods Three dose regimens were employed in the current study. 1) 0.03 mg kg−1 detomidine IV, 2) 0.2 mg kg−1 yohimbine IV and 3) 0.03 mg kg−1 detomidine IV followed 15 minutes later by 0.2 mg kg−1 yohimbine IV. Each horse received all three treatments with a minimum of 1 week between treatments. Blood samples were obtained and plasma analyzed for detomidine and yohimbine concentrations by liquid chromatography-mass spectrometry. Behavioral effects, heart rate and rhythm, glucose, packed cell volume and plasma proteins were monitored.
Results Yohimbine rapidly reversed the sedative effects of detomidine in the horse. Additionally, yohimbine effectively returned heart rate and the percent of atrio-ventricular conduction disturbances to pre-detomidine values when administered 15 minutes post-detomidine administration. Plasma glucose was significantly increased following detomidine administration. The detomidine induced hyperglycemia was effectively reduced by yohimbine administration. Effects on packed cell volume and plasma proteins were variable.
Conclusions and clinical relevance Intravenous administration of yohimbine effectively reversed detomidine induced sedation, bradycardia, atrio-ventricular heart block and hyperglycemia.