Abstract: This study aimed to compare the sedation quality and cardiorespiratory and behavioral effects of detomidine administered intravenously, either in intermittent boluses or as a continuous rate infusion, with butorphanol in horses pre-medicated with acepromazine for odontoplasty procedures. Unassigned: A prospective clinical study was conducted with fifteen adult horses randomly assigned to two groups: Bolus group (BG, = 7) and Infusion group (IG, = 8). Both groups received acepromazine premedication, followed by detomidine administration (bolus or infusion). Butorphanol was administered either as a bolus or continuous infusion during oral cavity evaluation (after detomidine). When sedation was inadequate, an additional bolus of detomidine combined with butorphanol was given. Physiological, sedative, and behavioral parameters were evaluated at multiple time points throughout the procedure. Data were analyzed using statistical models to assess differences between groups and across time points. Unassigned: Continuous infusion of detomidine resulted in superior sedation quality, greater stability, and a reduced need for rescue sedation ( < 0.001) compared to bolus administration. Horses in the BG total detomidine consumption was significantly influenced by procedure duration and the number of readministrations ( = 0.004). Despite improved sedation quality in IG, ataxia persisted longer post-procedure. Cardiovascular parameters showed expected α2-agonist effects, with transient reductions in heart rate and stable arterial pressure. Unassigned: Continuous infusion of detomidine with butorphanol provided more stable sedation, reducing the need for frequent redosing, but also led to prolonged ataxia. Future studies should explore alternative drug combinations to optimize sedation quality while minimizing ataxia and cardiorespiratory effects.
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Optimizing equine sedation by continuously infusing detomidine and butorphanol improves sedation stability but causes longer-lasting ataxia in horses undergoing dental procedures.
Study Purpose and Design
The study aimed to compare sedation quality and physiological/behavioral effects of detomidine administered via two methods: intermittent boluses versus continuous rate infusion.
Butorphanol was administered alongside detomidine, either as a bolus or continuous infusion.
Fifteen adult horses were premedicated with acepromazine before undergoing odontoplasty (dental) procedures.
They were randomly allocated into two groups:
Bolus Group (BG): received detomidine and butorphanol in boluses (n=7)
Infusion Group (IG): received detomidine and butorphanol as continuous infusions (n=8)
Behavioral responses (including ataxia, which means lack of muscle control)
When sedation was insufficient, an additional bolus of detomidine plus butorphanol was given (rescue sedation).
Parameters were assessed at multiple time points throughout the procedure.
Statistical models analyzed differences between groups and across time points.
Key Findings
The Infusion Group exhibited:
Superior sedation quality and greater sedation stability compared to the Bolus Group.
A significantly reduced need for rescue sedation (<0.001), indicating more consistent sedation levels.
Prolonged ataxia after the procedure, meaning horses took longer to regain normal muscle coordination.
In the Bolus Group, the total amount of detomidine consumed correlated significantly with:
Duration of the dental procedure.
Number of additional sedation doses administered (p=0.004).
Physiological effects observed were consistent with expected α2-adrenergic agonist drug characteristics:
Transient reduction in heart rate.
Stable arterial blood pressure throughout sedation.
Implications and Recommendations
Continuous infusion of detomidine combined with butorphanol allows for smoother, more stable sedation during dental procedures by avoiding peaks and troughs typical with intermittent boluses.
This method reduces the frequency and total amount of rescue sedation needed, which can be advantageous in procedural management.
A trade-off is that ataxia, or muscle uncoordinated movement, lasts longer post-procedure with continuous infusion, which may delay recovery and affect horse safety.
Cardiovascular parameters remain stable and within expected ranges indicating good safety profiles from a cardiac perspective.
Future research should investigate other drug combinations or dosing strategies to achieve high-quality sedation while minimizing prolonged ataxia and cardiovascular effects.
Cite This Article
APA
Arantes JA, Rabelo IP, Bermudes L, Lacerenza MD, Mendes RP, Corrêa RR, Yamada DI, Valadão CAA, Dória RGS.
(2025).
Optimizing equine standing sedation: continuous infusion of detomidine and butorphanol enhances stability but prolongs ataxia.
Front Vet Sci, 12, 1606585.
https://doi.org/10.3389/fvets.2025.1606585
Department of Veterinary Medicine, Faculty of Animal Sciences and Food Engineering (FZEA), University of Sao Paulo (USP), Pirassununga, SP, Brazil.
Rabelo, Isabela Peixoto
Department of Veterinary Medicine, Faculty of Animal Sciences and Food Engineering (FZEA), University of Sao Paulo (USP), Pirassununga, SP, Brazil.
Bermudes, Lucas
Department of Veterinary Medicine, Faculty of Animal Sciences and Food Engineering (FZEA), University of Sao Paulo (USP), Pirassununga, SP, Brazil.
Lacerenza, Milena Domingues
Department of Veterinary Medicine, Faculty of Animal Sciences and Food Engineering (FZEA), University of Sao Paulo (USP), Pirassununga, SP, Brazil.
Mendes, Rubens Peres
Department of Veterinary Medicine, Faculty of Animal Sciences and Food Engineering (FZEA), University of Sao Paulo (USP), Pirassununga, SP, Brazil.
Corrêa, Rodrigo Romero
Department of Surgery, School of Veterinary Medicine and Animal Science (FMVZ), University of São Paulo (USP), São Paulo, SP, Brazil.
Yamada, Diego Iwao
Department of Veterinary Medicine and Surgery, Faculty of Agricultural and Veterinary Sciences (UNESP), São Paulo State University, Jaboticabal, São Paulo, Brazil.
Valadão, Carlos Augusto de Araújo
Department of Veterinary Medicine and Surgery, Faculty of Agricultural and Veterinary Sciences (UNESP), São Paulo State University, Jaboticabal, São Paulo, Brazil.
Dória, Renata Gebara Sampaio
Department of Veterinary Medicine, Faculty of Animal Sciences and Food Engineering (FZEA), University of Sao Paulo (USP), Pirassununga, SP, Brazil.
Conflict of Interest Statement
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
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