Pharmacokinetics and pharmacodynamics of intravenous medetomidine in the horse

Pharmacokinetics and pharmacodynamics of intravenous dexmedetomidine in the horse

“…Medetomidine has been shown to have relatively short t 1/2(el) , with previously reported t 1/2(el) of 51.3 ± 13.1 min in ponies (Bettschart‐Wolfensberger et al ., ) and 29.1 ± 12.5 min in horses (Grimsrud et al ., ). Bettschart‐Wolfensberger et al .…”

“…A significant decrease in RR has been shown following the administration of dexmedetomidine in ponies (Bettschart‐Wolfensberger et al ., ) and medetomidine in horses (Grimsrud et al ., ). While RR decreased in most horses in this study, tachypnea was observed in three of them.…”

“…Possible factors that may account for the delayed T max could be the circulation time for the drug molecule to travel from the site of injection to the contralateral vein for blood sampling (Fang et al ., ) and the horse having a large blood volume and low HR resulting in a mixing phase of the drug in the central blood compartment. Another explanation might be the cardiovascular effects of dexmedetomidine (reduction in cardiac output and vasoconstriction) affecting the drug distribution, as similar delays in T max have been reported with both medetomidine (Grimsrud et al ., ) and detomidine (Grimsrud et al ., ) in horses.…”

“…The use of medetomidine, a short acting α 2 ‐AR agonist with the highest selectivity to the α 2 ‐AR (1620:1 vs. 160:1 for xylazine; Virtanen et al ., ; Scheinin et al ., ), has been described in horses (Yamashita et al ., ; Grimsrud et al ., ). Medetomidine has been reported to produce good sedation (Bryant et al ., ; Hobo et al ., ) and decrease mechanical nociception (Grimsrud et al ., ) but seems to cause a greater degree of ataxia when compared to xylazine in horses (Bryant et al ., ). The cardiovascular effects of medetomidine are dose‐dependent and similar to the effects observed with detomidine, but of shorter duration (Yamashita et al ., ).…”

Effects of Medetomidine Constant Rate Infusion on Sevoflurane Requirement, Cardiopulmonary Function, and Recovery Quality in Thoroughbred Racehorses Undergoing Arthroscopic Surgery

“…The short half-life of medetomidine and its selectivity and potency are suitable to be used as a constant rate infusion (CRI) for balanced anesthesia in horses [12][13][14][15]. It was reported that medetomidine CRI reduced the minimum alveolar concentration (MAC) of desflurane by 28% in experimental ponies [16].…”