Alpha2-adrenoceptor antagonists

Alpha2-agonists such as xylazine, detomidine and medetomidine are widely used for the sedation, hypnosis and immobilization of animals for a variety of surgical procedures, the α2-antagonists yohimbine, tolazoline, idazoxan and atipamezole being available for reversal of these effects. In veterinary medicine, α2-antagonists provide an easy and safe alternative for discontinuing sedation or anaesthesia when it is no longer required, thus facilitating rapid emergence and home-readiness. There are few human studies indicating the usefulness of this approach in clinical medicine. However, despite the fact that the concept of restraint and reversal has gained wide acceptance among veterinarians, there are currently no α2-adrenoceptor antagonists available for human use in the anaesthetic setting.