Effect of Xylazine and Butorphanol on Experimental Hind Limb Lameness in Horses

Effects of constant intravenous infusion of detomidine alone or combined with butorphanol or methadone for standing sedation in horses: A randomized clinical trial

This study aimed to evaluate the sedation degree, cardiopulmonary effects, and detomidine-sparing during dental occlusal adjustment in standing horses using a bolus and constant rate infusion (CRI) of detomidine alone or in combination with butorphanol or methadone. In this randomized, blinded clinical trial, 24 healthy adult horses were assigned to the detomidine (DT), detomidine-butorphanol (DB), or detomidine-methadone (DM) group. DT received an intravenous bolus of detomidine (20 μg/kg), followed by CRI at 20 μg/kg/h. DB received detomidine (10 μg/kg) and butorphanol (0.02 mg/kg) boluses with CRI at 10 μg/kg/h and 0.03 mg/kg/h, respectively. DM received detomidine (10 μg/kg) and methadone (0.2 mg/kg) boluses with CRI at 10 μg/kg/h and 0.05 mg/kg/h, respectively. For sedation rescue, an additional intravenous dose of detomidine (5 μg/kg) was administered without altering the CRI. Descriptive scales were used to assess sedation during and up to 12 h post-procedure. We recorded the respiratory rate (fr), heart rate (HR), systolic blood pressure (SBP), temperature, gastrointestinal motility, sedation depth, and detomidine rescue requirements. All treatments were found to reduce gastrointestinal motility and HR, whereas DM decreased fr. SBP exhibited transient elevations, and 22 sedation rescues were performed (2 in DM, 8 in DT, and 12 in DB). Considering the rescues, the total detomidine consumption resulted in significantly lower doses in DM (10.6 ± 2.32 μg/kg/h [mean ± standard deviation]) and DB (13.6 ± 4.58 μg/kg/h; both P < 0.0001) than in DT (22.4 ± 4.1 μg/kg/h). Opioid addition demonstrated a detomidine-sparing effect, significantly reducing detomidine requirement.

BEVA primary care clinical guidelines: Analgesia

Primary care guidelines provide a reference point to guide clinicians based on a systematic review of the literature, contextualised by expert clinical opinion. These guidelines develop a modification of the GRADE framework for assessment of research evidence (vetGRADE) and applied this to a range of clinical scenarios regarding use of analgesic agents. Key guidelines produced by the panel included recommendations that horses undergoing routine castration should receive intratesticular local anaesthesia irrespective of methods adopted and that horses should receive NSAIDs prior to surgery (overall certainty levels high). Butorphanol and buprenorphine should not be considered appropriate as sole analgesic for such procedures (high certainty). The panel recommend the continuation of analgesia for 3 days following castration (moderate certainty) and conclude that phenylbutazone provided superior analgesia to meloxicam and firocoxib for hoof pain/laminitis (moderate certainty), but that enhanced efficacy has not been demonstrated for joint pain. In horses with colic, flunixin and firocoxib are considered to provide more effective analgesia than meloxicam or phenylbutazone (moderate certainty). Given the risk of adverse events of all classes of analgesic, these agents should be used only under the control of a veterinary surgeon who has fully evaluated a horse and developed a therapeutic, analgesic plan that includes ongoing monitoring for such adverse events such as the development of right dorsal colitis with all classes of NSAID and spontaneous locomotor activity and potentially ileus with opiates. Finally, the panel call for the development of a single properly validated composite pain score for horses to allow accurate comparisons between medications in a robust manner.