Pharmacokinetics of detomidine and its metabolites following intravenous and intramuscular administration in horses

Abstract

These pharmacokinetic parameters provide information necessary for determination of peak plasma concentrations and clearance of detomidine in mature horses. The results suggest that, when a longer duration of plasma concentration is warranted, the i.m. route should be considered.

Influence of MK-467, a Peripherally Acting α2-Adrenoceptor Antagonist on the Disposition of Intravenous Dexmedetomidine in Dogs

“…We suggest that the marked reductions in cardiac output (cardiac output was less than the estimated total blood volume of the dog) affected the early disposition of dexmedetomidine to such an extent that the assumption of a maximum concentration reached immediately after intravenous administration should be rejected (i.e., incomplete early distribution within the central compartment). For example, Grimsrud et al (2009) reported a range of 1 to 6 min for the observed time to maximum concentration (T max ) of detomidine after intravenous administration to horses, which could be explained by cardiovascular effects (Nyman et al, 2009), comparable with the present study.…”

Sedation and mechanical antinociception after intravenous administration of detomidine in donkeys: a dosage–effect study

“…Using similar mechanical nociceptive devices and rates of application of force, basal MNT values in this study were comparable to those from previous studies on donkeys (Lizarraga and Beths 2012, Lizarraga and Janovyak 2013, Lizarraga and Castillo-Alcala 2014). However, Grint and others (2014) reported mean MNT values of 9.2 N using a rate of application of force of 0.4 N/second in donkeys. The difference in basal MNT values between studies may be due to the use of different actuators as it has been demonstrated in horses (Taylor and others 2012).…”

Pharmacokinetics and pharmacodynamics of intravenous dexmedetomidine in the horse

“…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.…”