Cullen L K
School of Veterinary Studies, Murdoch University, Australia.
Br Vet J. 1996 Sep;152(5):519-35. doi: 10.1016/s0007-1935(96)80005-4.
Medetomidine is a relatively new sedative analgesic in dogs and cats but some precautions are required when using it. It is a potent alpha 2-adrenoceptor agonist and stimulates receptors centrally to produce dose-dependent sedation and analgesia and receptors centrally and peripherally to cause marked bradycardia and decrease the cardiac output. While hypotension occurs frequently, higher doses of the sedative can raise the blood pressure due to an affect on peripheral receptors. Slowing of the respiratory rate is a frequent effect of medetomidine with some dogs showing signs of cyanosis. Other actions that follow medetomidine use are slowing of gastrointestinal motility, hypothermia, changes to endocrine function and, occasionally, vomiting and muscle twitching. The clinical use of medetomidine in dogs and cats is discussed. Recommended dose rates are presented along with precautions that should be taken when it is used alone for sedation, as an anaesthetic premedicant or in combination with ketamine, propofol or opioids. Hypoxaemia occurs frequently in dogs given medetomidine and propofol. The actions of medetomidine can be rapidly reversed with the specific alpha 2-adrenoceptor antagonist, atipamezole, which is an advantage because undesirable and sedative actions of medetomidine can be terminated.
美托咪定是一种相对新型的用于犬猫的镇静镇痛药，但使用时需要一些注意事项。它是一种强效的α2肾上腺素能受体激动剂，可刺激中枢受体产生剂量依赖性的镇静和镇痛作用，并刺激中枢和外周受体导致明显的心动过缓并降低心输出量。虽然低血压经常发生，但较高剂量的镇静剂由于对外周受体的影响可使血压升高。呼吸频率减慢是美托咪定常见的作用，一些犬会出现发绀迹象。使用美托咪定后的其他作用包括胃肠蠕动减慢、体温过低、内分泌功能改变，偶尔还会出现呕吐和肌肉抽搐。文中讨论了美托咪定在犬猫中的临床应用。给出了推荐剂量率以及单独用于镇静、作为麻醉前用药或与氯胺酮、丙泊酚或阿片类药物联合使用时应采取的注意事项。使用美托咪定和丙泊酚的犬经常会出现低氧血症。美托咪定的作用可用特异性α2肾上腺素能受体拮抗剂阿替美唑迅速逆转，这是一个优点，因为美托咪定的不良和镇静作用可以终止。
