Effects of a medetomidine and tramadol combination in horses

Behavioral and cardiorespiratory effects of a medetomidine and tramadol combination in horses
J Vet Sci. 2026 Mar;27(2):e17. doi: 10.4142/jvs.25252.
Authors
Ahram Kim 1 , Inhyung Lee 2 , Kyuyoung Lee 3 , Eun-Bee Lee 4 , Jong-Pil Seo 5
Affiliations

1 Equine Clinic, Jeju Racing Resources Management Team, Korea Racing Authority, Jeju 63066, Korea.
2 Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea.
3 AI-Bio Convergence Research Institute, Soongsil University, Seoul 06978, Korea.
4 Department of Veterinary Medicine, College of Veterinary Medicine and Veterinary Medical Research Institute, Jeju National University, Jeju 63243, Korea.
5 Department of Veterinary Medicine, College of Veterinary Medicine and Veterinary Medical Research Institute, Jeju National University, Jeju 63243, Korea. jpseo@jejunu.ac.kr.

PMID: 41947678
DOI: 10.4142/jvs.25252

Abstract

Importance: The use of combinations of sedative and analgesic drugs during standing procedures in horses is necessary to provide reliable sedation with minimal ataxia and reduced responses to surgical or other stimuli in horses.

Objective: This study assessed the behavioral and cardiorespiratory effects of medetomidine (M) administered with and without tramadol (T) in horses.

Methods: Eight horses were sedated intravenously with M (5 µg/kg) alone or with T (2 mg/kg) in a arandomized, blind, two-way crossover trial. Behavioral responses, including head height above the ground (HHAG), postural instability (PI), and response to pressure stimulus (RPS), and cardiorespiratory responses, including vital variables and blood analyses, were assessed following administration.

Results: There were no clinically meaningful differences in cardiorespiratory values, HHAG, or PI between the groups. The RPS score over the scapula was significantly higher in the medetomidine and tramadol (MT) group (p < 0.05) and a trend towards a higher RPS score over the femur was observed (p = 0.08) in the MT group. Heart rate decreased significantly below baseline from 10 to 40 min in both treatments. Conclusions and relevance: These results suggest that the MT combination may provide sufficient sedation and analgesia with minimal cardiorespiratory changes in horses. Keywords: Horses; alpha-2 adrenergic agonist; atypical opioid; somatic nociceptive threshold; standing sedation. © 2026 The Korean Society of Veterinary Science. Conflict of interest statement The authors declare no conflicts of interest.