Effects of vatinoxan in horses sedated with detomidine and butorphanol for gastroscopy: a randomized clinical study.

Overview

• This study evaluated how the drug vatinoxan affects sedation outcomes and side effects in horses sedated with detomidine and butorphanol for gastroscopy.
• The research specifically examined heart rate, digestive sounds, blood glucose, and insulin levels to assess whether vatinoxan reduces negative side effects associated with alpha2-adrenergic sedatives.

Background and Purpose

• Alpha2-adrenergic sedatives like detomidine are commonly used in horses for procedures such as gastroscopy but can cause side effects including decreased heart rate (bradycardia), reduced gastrointestinal motility (reflected by decreased borborygmi), and altered glucose and insulin levels.
• Vatinoxan is a peripheral alpha2-adrenoceptor antagonist shown in experimental studies to reduce some of these side effects by blocking peripheral receptors while presumably maintaining sedation centrally.
• The study aimed to investigate if adding vatinoxan to a standard sedative regimen (detomidine and butorphanol) would improve side effect profiles in clinical, client-owned horses.

Study Design and Methods

• The study was a randomized clinical trial involving 22 client-owned horses undergoing gastroscopy.
• Two treatment groups were formed:
  • DB group: Detomidine hydrochloride (12 μg/kg IV) + butorphanol tartrate (12 μg/kg IV), n=11 horses.
  • DBV group: Same as DB plus vatinoxan hydrochloride (200 μg/kg IV), n=11 horses.
• Data collection included:
  • Heart rate and borborygmi (gut sounds) scored by auscultation before and up to 240 minutes post drug administration.
  • Assessment of sedation level to ensure adequate sedation for gastroscopy.
  • Blood sampling for glucose measurements (via portable glucometer immediately) and serum insulin and triglyceride analysis from frozen samples.
  • Gastroscopy performed within 30 minutes after sedation was initiated.

Key Findings

• All horses in both groups achieved adequate sedation for performing gastroscopy.
• Heart rate:
  • The DB group experienced a more notable decrease in heart rate compared to the DBV group.
  • Vatinoxan attenuated the bradycardia caused by detomidine and butorphanol sedation.
• Borborygmi:
  • The horses receiving vatinoxan (DBV group) maintained gut sounds closer to baseline, indicating better preservation of gastrointestinal motility.
  • In the DB group without vatinoxan, borborygmi decreased more significantly.
• Glucose and Insulin:
  • Detomidine typically inhibits insulin secretion, resulting in increased blood glucose.
  • In the DBV group, the rise in blood glucose and the suppression of insulin secretion were less pronounced than in the DB group.
  • This suggests vatinoxan helps moderate metabolic side effects related to insulin and glucose.

Conclusions and Implications

• Vatinoxan improved the side effect profile of detomidine and butorphanol sedation in horses without compromising sedative efficacy.
• Specifically, it helped prevent excessive heart rate reduction and preserved gastrointestinal motility.
• It also attenuated detomidine’s negative impact on insulin secretion and prevented significant hyperglycemia.
• These findings suggest that adding vatinoxan may be beneficial in clinical equine sedation protocols, enhancing cardiovascular and metabolic safety during procedures like gastroscopy.
• Further research could explore optimal dosing and assess potential benefits in other veterinary sedation settings.