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

The peripheral alpha2-adrenoceptor antagonist vatinoxan attenuated the side effects of alpha2-adrenergic sedatives in experimental studies in horses. This clinical study investigated the effects of vatinoxan in horses sedated for gastroscopy with detomidine and butorphanol. Client-owned horses were randomly allocated to receive one of the following two intravenous treatments: detomidine hydrochloride (HCl) (12 μg/kg) + butorphanol tartrate (12 μg/kg) (DB; n = 11) or DB + vatinoxan HCl (200 μg/kg) (DBV; n = 11). Borborygmi score and heart rate were recorded by auscultation. Sedation level was evaluated and blood samples were collected before drug administration and up to 240 min thereafter. Gastroscopy was performed within 30 min of sedation. Glucose concentration was measured immediately with a portable glucometer. Serum insulin and triglyceride concentrations were analysed from frozen samples. Sedation level was adequate in all horses for gastroscopy. Overall heart rate decreased significantly more with DB than with DBV. In general, audible borborygmi, blood insulin, and glucose concentrations remained closer to baseline values with DBV compared DB. In conclusion, vatinoxan improved borborygmi and alleviated the decreased heart rate in horses sedated with detomidine and butorphanol for gastroscopy. The detomidine-induced inhibition to insulin secretion and thus the increase in blood glucose concentration were attenuated by vatinoxan. Vatinoxan may be a beneficial addition to equine sedation protocols in clinical settings.