CAT – Do opioids cause colic?

Morphine is a full opioid mu-receptor agonist and a potent analgesic agent used in both human and veterinary medicine. Mu-receptor agonists have been reported to reduce propulsive gut motility [1]. Consequently, morphine administration in horses has historically been associated with a risk of colic. With all drug administration it is important to balance possible adverse effects against clinical benefits. Morphine is most commonly administered perioperatively, both for its analgesic effects [2] and, potentially, providing an improved recovery from anaesthesia [3,4]. Considering the effect of morphine on equine gastrointestinal motility and the potential clinical benefits of perioperative administration, it is important to critically evaluate the literature pertaining to the use of morphine in this common clinical scenario ...