Partial intravenous anaesthesia in the horse: a review of intravenous agents used to supplement equine inhalation anaesthesia. Part 2: opioids and alpha‐2 adrenoceptor agonists

ObjectiveTo review the literature with regard to the use of different intravenous agents as supplements to inhalational anaesthesia in horses. The Part 2 of this review will focus in the use of opioids and a₂-agonists.Databases usedPubmed and Web of Science. Search terms: horse, inhalant anaesthesia, balanced anaesthesia, partial intravenous anaesthesia, opioids, morphine, pethidine, butorphanol, methadone, fentanyl, alfentanil, remifentanil, sufentanil, xylazine, romifidine, detomidine, medetomidine and dexmedetomidine.ConclusionsDifferent drugs and their combinations can be administered systemically in anaesthetized horses aiming to reduce the amount of the volatile agent while improving the recovery qualities and providing a multimodal analgesic approach. However, full studies as to whether these techniques improve cardiopulmonary status are not always available and potential disadvantages should also be considered.