Tachycardia and muscle tremors following intravenous administration of detomidine to a horse undergoing standing surgery.
Abstract: Detomidine hydrochloride is an alpha adrenoceptor agonist that is commonly used in equine practice to provide sedation and analgesia for horses undergoing standing procedures. Reported effects following intravenous administration of detomidine in horses include bradycardia, bradyarrhythmias, transient hypertension, sweating, piloerection and dose-dependent sedation, ataxia and analgesia. This case report describes a novel response characterised by tachycardia and profound muscle tremors following the administration of intravenous detomidine to a horse undergoing a standing procedure.
© 2025 Australian Veterinary Association.
Publication Date: 2025-11-25 PubMed ID: 41288302DOI: 10.1111/avj.70041Google Scholar: Lookup The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Case Reports
- Journal Article
Summary
This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.
Tachycardia and muscle tremors can occur as unexpected side effects following intravenous detomidine administration in horses, though typically detomidine causes decreased heart rate and sedation.
Background on Detomidine Use in Horses
- Detomidine hydrochloride is an alpha adrenoceptor agonist used in equine veterinary medicine.
- It is commonly administered to provide sedation and pain relief during standing surgical procedures.
- Typical cardiovascular effects include decreased heart rate (bradycardia) and possible arrhythmias (bradyarrhythmias).
- Other known side effects include temporary high blood pressure (transient hypertension), sweating, hair standing on end (piloerection), and dose-dependent sedation, ataxia (loss of coordination), and analgesia.
Purpose and Description of the Case Report
- The case report aims to describe an unusual adverse reaction to intravenous detomidine in a horse undergoing standing surgery.
- The horse developed tachycardia, which is an abnormally fast heart rate, contrasting with the commonly observed bradycardia.
- In addition to tachycardia, the horse exhibited profound muscle tremors, which are involuntary, rhythmic muscle contractions.
Significance of the Findings
- This reaction has not been previously reported following intravenous detomidine administration in horses.
- The occurrence of tachycardia and muscle tremors suggests that some horses may respond paradoxically or have idiosyncratic reactions to the drug.
- Understanding this possible reaction is important for veterinarians to monitor horses closely after detomidine administration during standing procedures.
- Knowledge of this potential side effect can inform decision-making, risk assessment, and management of adverse events.
Clinical Implications
- Veterinarians should be aware that although detomidine typically causes decreased heart rate and sedation, tachycardia is possible.
- Muscle tremors following administration may require supportive care or modification of anesthetic/sedation protocols.
- Continuous monitoring of cardiovascular and neuromuscular status is advised after intravenous detomidine, especially during standing surgeries where the horse is conscious and reactions can be problematic.
Cite This Article
APA
Melanie Catanchin CS, Bell J, Labens R, Quinn CT.
(2025).
Tachycardia and muscle tremors following intravenous administration of detomidine to a horse undergoing standing surgery.
Aust Vet J, 104(3), 167-170.
https://doi.org/10.1111/avj.70041 Publication
Researcher Affiliations
- School of Agricultural, Environmental and Veterinary Sciences, Charles Sturt University, Wagga Wagga, New South Wales, Australia.
- School of Agricultural, Environmental and Veterinary Sciences, Charles Sturt University, Wagga Wagga, New South Wales, Australia.
- School of Agricultural, Environmental and Veterinary Sciences, Charles Sturt University, Wagga Wagga, New South Wales, Australia.
- School of Agricultural, Environmental and Veterinary Sciences, Charles Sturt University, Wagga Wagga, New South Wales, Australia.
MeSH Terms
- Animals
- Horses
- Imidazoles / adverse effects
- Imidazoles / administration & dosage
- Tremor / chemically induced
- Tremor / veterinary
- Horse Diseases / chemically induced
- Tachycardia / chemically induced
- Tachycardia / veterinary
- Male
- Adrenergic alpha-2 Receptor Agonists / adverse effects
- Adrenergic alpha-2 Receptor Agonists / administration & dosage
- Administration, Intravenous / veterinary
- Female
- Standing Position
References
This article includes 21 references
- Owens CD, Hughes KJ, Hilbert BJ. Survey of equine castration techniques, preferences and outcomes among Australian veterinarians.. Aust Vet J 2018;96(1–2):39–45.
- England GCW, Clarke KW. Alpha(2) adrenoceptor agonists in the horse ‐ a review.. Br Vet J 1996;152(6):641–657.
- Yamashita K, Tsubakishita S, Futaoka S. Cardiovascular effects of medetomidine, detomidine and xylazine in horses.. J Vet Med Sci 2000;62(10):1025–1032.
- Clarke KW, Taylor PM. Detomidine: a new sedative for horses.. Equine Vet J 1986;18(5):366–370.
- Nunez E, Steffey EP, Ocampo L. Effects of alpha₂‐adrenergic receptor agonists on urine production in horses deprived of food and water.. Am J Vet Res 2004;65(10):1342–1346.
- Peters DF, Erfle JB, Slobojan GT. Aggressive behavior associated with the use of xylazine and detomidine.. Proceedings of the Annual Convention AAEP (Vol 44) 1998.
- Corley K, Stephen J. The equine hospital manual.. .
- Virtanen R, Savola J-M, Saano V. Characterization of the selectivity, specificity and potency of medetomidine as an α2‐adrenoceptor agonist.. Eur J Pharmacol 1988;150(1):9–14.
- Riviere JE, Papich MG. Veterinary pharmacology and therapeutics.. .
- Loomes K, Anderson J. Intra‐splenic administration of phenylephrine in a horse to induce splenic contraction in a case of nephrosplenic entrapment of the large colon non‐responsive to intravenous phenylephrine administration.. Equine Vet Educ 2020;32(11):e219–e222.
- Hunt RJ, Brandon CI, McCann ME. Effects of acetylpromazine, xylazine, and vertical load on digital arterial blood flow in horses.. Am J Vet Res 1994;55(3):375–378.
- Marntell S, Nyman G, Funkquist P. Effects of acepromazine on pulmonary gas exchange and circulation during sedation and dissociative anaesthesia in horses.. Vet Anaesth Analg 2005;32(2):83–93.
- England G, Clarke K, Goossens L. A comparison of the sedative effects of three α2‐adrenoceptor agonists (romifidine, detomidine and xylazine) in the horse.. J Vet Pharmacol Ther 1992;15(2):194–201.
- Hamm D, Turchi P, Jöchle W. Sedative and analgesic effects of detomidine and romifidine in horses.. Vet Rec 1995;136(13):324–327.
- Hamm D, Jöchle W. Sedation and analgesia with dormosedan®(Detomidine hydrochloride) or acepromazlne for suturing of the vulvar lips in mares (Caslick's surgery).. J Equine Vet Sci 1991;11(2):86–88.
- Clarke KW, Paton BS. Combined use of detomidine with opiates in the horse.. Equine Vet J 1988;20(5):331–334.
- Gardner RB, White GW, Ramsey DS. Efficacy of sublingual administration of detomidine gel for sedation of horses undergoing veterinary and husbandry procedures under field conditions.. J Am Vet Med Assoc 2010;237(12):1459–1464.
- Fielding CL, Magdesian KG, Aguilera‐Tejero E s. Equine fluid therapy.. .
- Barnes A, Kingston J, Beetson S. Endurance veterinarians detect physiologically compromised horses in a 160 km ride.. Equine Vet J 2010;42(s38):6–11.
- White SL. Fluid, electrolyte, and Acid‐Base balances in three‐day, combined‐training horses.. Vet Clin North Am Equine Pract 1998;14(1):137–145.
- Beyer MJ, Freestone JF, Reimer JM. Idiopathic hypocalcemia in foals.. J Vet Intern Med 1997;11(6):356–360.
Citations
This article has been cited 0 times.Use Nutrition Calculator
Check if your horse's diet meets their nutrition requirements with our easy-to-use tool Check your horse's diet with our easy-to-use tool
Talk to a Nutritionist
Discuss your horse's feeding plan with our experts over a free phone consultation Discuss your horse's diet over a phone consultation
Submit Diet Evaluation
Get a customized feeding plan for your horse formulated by our equine nutritionists Get a custom feeding plan formulated by our nutritionists