“…A lthough analgesics or antinociceptive agents are now widely used in domestic animals, their usage has been very limited in reptiles, such as green iguanas (Iguana iguana). [1][2][3] The number of reports 4 of the use of analgesic agents in reptiles is increasing, but most have been based on anecdotal experiences, with dosages often extrapolated from other species, such as birds. Butorphanol, a κ-opioid receptor a agonist and a µ-opioid receptor a antagonist, has historically been used to pro-Assessments of thermal antinociceptive effects of butorphanol and human observer effect on quantitative evaluation of analgesia in green iguanas (Iguana iguana)…”