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Home / Equine Research Bank / Br Vet J / Alpha 2 adrenoceptor agonists in the horse–a review.
The British veterinary journal1996; 152(6); 641-657; doi: 10.1016/s0007-1935(96)80118-7

Alpha 2 adrenoceptor agonists in the horse–a review.

Abstract: In recent years the usefulness of the alpha 2 adrenoceptor agonist drugs has been recognized in equine practice. Several agents have become available and are now licensed for use in a number of countries. The principle actions of all alpha 2 adrenoceptor agonists are similar, in that they produce a reduction in heart rate and alteration of heart rhythm, an initial hypertension followed by a prolonged hypotension, a decrease in the cardiac output and respiratory depression. For clinical purposes, these agents produce sedation and analgesia, they are useful for premedication and markedly potentiate the effects of other sedative/analgesic agents. Differences in receptor specificity between the alpha 2 adrenoceptor agonists results in the distinguishing characteristics of the individual agents, particularly with respect to their duration of action, sedative effect and analgesic properties; their cardiopulmonary effects are however similar, when equipotent sedative doses are administered. When used in combination with other agents, the alpha 2 adrenoceptor agonists all appear to act in a similar manner, with the greatest difference being related to their duration of action.
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Publication Date: 1996-11-01 PubMed ID: 8979422DOI: 10.1016/s0007-1935(96)80118-7Google Scholar: Lookup
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  • Journal Article
  • Review

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.

The research article reviews the use and effects of alpha 2 adrenoceptor agonists drugs on horses, highlighting their impact on heart rate, blood pressure, and respiratory functions, as well as their utility as sedative and analgesic agents.

Introduction to Alpha 2 Adrenoceptor Agonists

  • The paper begins by stating that the utility of Alpha 2 adrenoceptor agonists has been recognized in equine (horse) practice in recent years.
  • These drugs are now licensed and available for use in many countries.

Actions of Alpha 2 Adrenoceptor Agonists

  • Alpha 2 adrenoceptor agonists share similar key actions – they reduce heart rate, alter heart rhythm, initially cause hypertension which later turns to prolonged hypotension, decrease cardiac output, and induce respiratory depression.

Clinical Applications of Alpha 2 Adrenoceptor Agonists

  • The research notes the usefulness of these drugs in clinical contexts – they induce sedation and analgesia in horses, making them valuable for premedication.
  • In addition, these drugs can enhance the effects of other sedative or analgesic agents.

Receptor Specificity and Effects

  • Although they have similar function, different alpha 2 adrenoceptor agonists can have varying characteristics due to different receptor specificity. These distinguishing features can impact their duration of action, sedative effect, and analgesic properties.
  • However, when it comes to cardiopulmonary effects, all these drugs behave similarly if equal sedative doses are administered.

Use in Combination with Other Agents

  • When used in combination with other drugs, the greatest difference seen among the alpha 2 adrenoceptor agonists is related to their duration of action.

Cite This Article

APA
England GC, Clarke KW. (1996). Alpha 2 adrenoceptor agonists in the horse–a review. Br Vet J, 152(6), 641-657. https://doi.org/10.1016/s0007-1935(96)80118-7

Publication

The British veterinary journal
ISSN: 0007-1935
NlmUniqueID: 0372554
Country: England
Language: English
Volume: 152
Issue: 6
Pages: 641-657

Researcher Affiliations

England, G C
  • Department of Farm Animal and Equine Medicine and Surgery, Royal Veterinary College, University of London, North Mymms, Hatfield, UK.
Clarke, K W

    MeSH Terms

    • Adrenergic alpha-2 Receptor Agonists
    • Adrenergic alpha-Agonists / pharmacology
    • Analgesics / pharmacology
    • Animals
    • Blood Pressure / drug effects
    • Blood Pressure / physiology
    • Clonidine / pharmacology
    • Dose-Response Relationship, Drug
    • Heart Rate / drug effects
    • Heart Rate / physiology
    • Horses / physiology
    • Hypnotics and Sedatives / pharmacology
    • Imidazoles / pharmacology
    • Medetomidine
    • Respiration / drug effects
    • Respiration / physiology
    • Xylazine / pharmacology

    Citations

    This article has been cited 30 times.
    1. Marzok M, Almubarak AI, Babiker H, Kandeel M, El-Hawari SF, El-Khodery S. Comparative evaluation of sedative and anti-nociceptive effects of epidural romifidine, romifidine-lidocaine, and lidocaine in donkeys (Equus asinus). Front Vet Sci 2022;9:966715.
      doi: 10.3389/fvets.2022.966715pubmed: 36570502google scholar: lookup
    2. Rabbogliatti V, Amari M, Brioschi FA, Di Cesare F, Zani DD, De Zani D, Di Giancamillo M, Cagnardi P, Ravasio G. Use of dexmedetomidine repeated subcutaneous administration for balanced anaesthesia in horses. BMC Vet Res 2022 Jul 11;18(1):269.
      doi: 10.1186/s12917-022-03350-0pubmed: 35818051google scholar: lookup
    3. Cock G, Blakeney Z, Hernandez JA, DeNotta S. Opioid-free sedation for atlantoaxial cerebrospinal fluid collection in adult horses. J Vet Intern Med 2022 Sep;36(5):1812-1819.
      doi: 10.1111/jvim.16450pubmed: 35639966google scholar: lookup
    4. Esmailinejad MR, Masoudifard M, Azari O, Sakhaee E, Ghalekhani N. Echocardiographic assessment of intravenous administration of medetomidine and xylazine hydrochloride at different sedative doses in one-humped camel calves (Camelus dromedarious). Vet Res Forum 2022 Mar;13(1):39-46.
      doi: 10.30466/vrf.2019.112347.2675pubmed: 35601775google scholar: lookup
    5. Meuffels J, Bertschinger H, Tindall B, Pohlin F, Luther-Binoir I, Trivedi S, Boshoff CR, Lueders I. Arterial Blood Gases and Cardiorespiratory Parameters in Etorphine-Medetomidine-Midazolam Immobilized Free-Ranging and Game-Farmed Southern White Rhinoceroses (Ceratotherium simum simum) Undergoing Electro-Ejaculation. Front Vet Sci 2022;9:862100.
      doi: 10.3389/fvets.2022.862100pubmed: 35573418google scholar: lookup
    6. Nissen SD, Weis R, Krag-Andersen EK, Hesselkilde EM, Isaksen JL, Carstensen H, Kanters JK, Linz D, Sanders P, Hopster-Iversen C, Jespersen T, Pehrson S, Buhl R. Electrocardiographic characteristics of trained and untrained standardbred racehorses. J Vet Intern Med 2022 May;36(3):1119-1130.
      doi: 10.1111/jvim.16427pubmed: 35488721google scholar: lookup
    7. Wise IK, Klöppel H, Leece EA. Comparison of two doses of ketamine for induction of anaesthesia in ponies undergoing field castration. Open Vet J 2021 Oct-Dec;11(4):747-754.
      doi: 10.5455/OVJ.2021.v11.i4.27pubmed: 35070872google scholar: lookup
    8. Meuffels J, Lueders I, Bertschinger H, Luther-Binoir I, Pohlin F, Gerber L, Tindall B. Cardiopulmonary Parameters and Arterial Blood Gases During Etorphine-Medetomidine-Midazolam Immobilization in Free-Ranging Black Rhinoceroses (Diceros bicornis) Undergoing Electro-Ejaculation-A Preliminary Study. Front Vet Sci 2021;8:740614.
      doi: 10.3389/fvets.2021.740614pubmed: 34926635google scholar: lookup
    9. Jarosinski SK, Simon BT, Hatfield R, Matthews NS, Arnold CE. The effects of xylazine or detomidine when used as a pre-anesthetic sedative on recovery quality and duration in horses undergoing elective equine castration. Can Vet J 2021 Sep;62(9):982-986.
      pubmed: 34475584
    10. Straticò P, Carluccio A, Varasano V, Guerri G, Suriano R, Robbe D, Cerasoli I, Petrizzi L. Analgesic Effect of Butorphanol during Castration in Donkeys under Total Intravenous Anaesthesia. Animals (Basel) 2021 Aug 9;11(8).
      doi: 10.3390/ani11082346pubmed: 34438803google scholar: lookup
    11. Gozalo-Marcilla M, Ringer SK. Recovery after General Anaesthesia in Adult Horses: A Structured Summary of the Literature. Animals (Basel) 2021 Jun 14;11(6).
      doi: 10.3390/ani11061777pubmed: 34198637google scholar: lookup
    12. Wiederkehr A, Barbarossa A, Ringer SK, Jörger FB, Bryner M, Bettschart-Wolfensberger R. Clinical Randomized Comparison of Medetomidine and Xylazine for Isoflurane Balanced Anesthesia in Horses. Front Vet Sci 2021;8:603695.
      doi: 10.3389/fvets.2021.603695pubmed: 33959647google scholar: lookup
    13. de Oliveira AR, Gozalo-Marcilla M, Ringer SK, Schauvliege S, Fonseca MW, Trindade PHE, Puoli Filho JNP, Luna SPL. Development, Validation, and Reliability of a Sedation Scale in Horses (EquiSed). Front Vet Sci 2021;8:611729.
      doi: 10.3389/fvets.2021.611729pubmed: 33665216google scholar: lookup
    14. Masoudifard M, Esmailinejad MR, Sakhaee E, Azari O, Vafaei R, Ghalekhani N. Pulsed wave Doppler echocardiographic assessment after sedation by intravenous injection of medetomidine and xylazine hydrochloride on cardiac output and systolic time intervals in one-humped camel calves (Camelus dromedarious). Iran J Vet Res 2020 Fall;21(4):257-262.
      pubmed: 33584837
    15. Al Hussein H, Al Hussein H, Sircuta C, Cotoi OS, Movileanu I, Nistor D, Cordos B, Deac R, Suciu H, Brinzaniuc K, Simionescu DT, Harpa MM. Challenges in Perioperative Animal Care for Orthotopic Implantation of Tissue-Engineered Pulmonary Valves in the Ovine Model. Tissue Eng Regen Med 2020 Dec;17(6):847-862.
      doi: 10.1007/s13770-020-00285-1pubmed: 32860183google scholar: lookup
    16. Blohm KO, Tichy A, Nell B. Clinical utility, dose determination, and safety of ocular contrast-enhanced ultrasonography in horses: A pilot study. Vet Ophthalmol 2020 Mar;23(2):331-340.
      doi: 10.1111/vop.12730pubmed: 31799804google scholar: lookup
    17. Ida KK, Sauvage A, Gougnard A, Grauwels M, Serteyn D, Sandersen C. Use of Nasotracheal Intubation during General Anesthesia in Two Ponies with Tracheal Collapse. Front Vet Sci 2018;5:42.
      doi: 10.3389/fvets.2018.00042pubmed: 29594157google scholar: lookup
    18. Romagnoli N, Al-Qudah KM, Armorini S, Lambertini C, Zaghini A, Spadari A, Roncada P. Pharmacokinetic profile and partitioning in red blood cells of romifidine after single intravenous administration in the horse. Vet Med Sci 2017 Nov;3(4):187-197.
      doi: 10.1002/vms3.70pubmed: 29152313google scholar: lookup
    19. Hopster K, Wittenberg-Voges L, Kästner SBR. Xylazine infusion in isoflurane-anesthetized and ventilated healthy horses: Effects on cardiovascular parameters and intestinal perfusion. Can J Vet Res 2017 Oct;81(4):249-254.
      pubmed: 29081581
    20. Umar MA, Fukui S, Kawase K, Itami T, Yamashita K. Cardiovascular effects of total intravenous anesthesia using ketamine-medetomidine-propofol (KMP-TIVA) in horses undergoing surgery. J Vet Med Sci 2015 Mar;77(3):281-8.
      doi: 10.1292/jvms.14-0370pubmed: 25409552google scholar: lookup
    21. Kullmann A, Sanz M, Fosgate GT, Saulez MN, Page PC, Rioja E. Effects of xylazine, romifidine, or detomidine on hematology, biochemistry, and splenic thickness in healthy horses. Can Vet J 2014 Apr;55(4):334-40.
      pubmed: 24688132
    22. Dalla Costa E, Minero M, Lebelt D, Stucke D, Canali E, Leach MC. Development of the Horse Grimace Scale (HGS) as a pain assessment tool in horses undergoing routine castration. PLoS One 2014;9(3):e92281.
      doi: 10.1371/journal.pone.0092281pubmed: 24647606google scholar: lookup
    23. Bauquier SH, Kona-Boun JJ. [Comparison of the effects of xylazine and romifidine administered perioperatively on the recovery of anesthetized horses]. Can Vet J 2011 Sep;52(9):987-93.
      pubmed: 22379199
    24. Seo JP, Son WG, Gang S, Lee I. Sedative and analgesic effects of intravenous xylazine and tramadol on horses. J Vet Sci 2011 Sep;12(3):281-6.
      doi: 10.4142/jvs.2011.12.3.281pubmed: 21897102google scholar: lookup
    25. Cruz FS, Carregaro AB, Machado M, Antonow RR. Sedative and cardiopulmonary effects of buprenorphine and xylazine in horses. Can J Vet Res 2011 Jan;75(1):35-41.
      pubmed: 21461193
    26. Cruz AM, Coté N, McDonell WN, Geor RJ, Wilson BA, Monteith G, Li R. Postoperative effects of anesthesia and surgery on resting energy expenditure in horses as measured by indirect calorimetry. Can J Vet Res 2006 Oct;70(4):257-62.
      pubmed: 17042377
    27. Kerr CL, McDonell WN, Young SS. Cardiopulmonary effects of romifidine/ketamine or xylazine/ketamine when used for short duration anesthesia in the horse. Can J Vet Res 2004 Oct;68(4):274-82.
      pubmed: 15581222
    28. Thorn CA, Wilson DV, Wang S, Horne WA. Impact of sequential administration of detomidine, butorphanol, and midazolam on sedation, ataxia, stimulus response, and bispectral index in horses. Front Vet Sci 2025;12:1691137.
      doi: 10.3389/fvets.2025.1691137pubmed: 41200548google scholar: lookup
    29. Hamed MA, Zahran IS, Samy A, Fayad E, Katouah HA, Farrag F, Abumandour MMA, Sobhy A, Elolimy AA, Okene IA, Shukry M, Elgioushy M. Comparative antinociceptive and sedative effects of epidural romifidine and xylazine in dromedary Camels (Camelus dromedarius). BMC Vet Res 2025 May 17;21(1):353.
      doi: 10.1186/s12917-025-04706-ypubmed: 40382642google scholar: lookup
    30. Mascaró Triedo CE, Karar S, Abunemeh M, Portier K. Effect of nose twitching on the pupillary dilation in awake and anesthetized horses. Front Vet Sci 2024;11:1412755.
      doi: 10.3389/fvets.2024.1412755pubmed: 39036796google scholar: lookup
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