Miettinen T J, Kanto J H, Salonen M A, Scheinin M
Department of Anesthesiology and Pharmacology, University of Turku, Finland.
Anesth Analg. 1996 Apr;82(4):817-20. doi: 10.1097/00000539-199604000-00024.
Tizanidine, an imidazoline derivative with alpha 2-receptor-mediated central muscle relaxant activity, is in widespread clinical use for the treatment of spasticity. To evaluate its possible role in anesthesia we assessed the sedative and sympatholytic effects of orally administered tizanidine in a double-blind, placebo-controlled, randomized, cross-over study in six healthy male volunteers. Three different doses of tizanidine (4, 8, and 12 mg) were tested and compared to clonidine 150 micrograms. The sedative and sympatholytic effects of tizanidine 12 mg were comparable in magnitude to those of clonidine 150 micrograms, but the effects of clonidine were longer lasting. Similarly, the observed decreases in arterial blood pressure (diastolic, 13% and 19%; systolic, 10% and 8% for tizanidine and clonidine, respectively) and salivation were comparable in magnitude but of shorter duration after tizanidine 12 mg than after clonidine. Clonidine and tizanidine 12 mg had also similar effects on the secretion of growth hormone. Our results indicate that the effects of a single 12-mg oral dose of tizanidine resemble those of 150 micrograms oral clonidine, but are of shorter duration. Tizanidine may thus be a useful alternative to clonidine as an orally active, short-acting alpha 2-adrenoceptor agonist in the perioperative period.
替扎尼定是一种具有α2受体介导的中枢性肌肉松弛活性的咪唑啉衍生物，在临床上广泛用于治疗痉挛。为了评估其在麻醉中的可能作用，我们在一项双盲、安慰剂对照、随机、交叉研究中，对6名健康男性志愿者口服替扎尼定的镇静和抗交感神经作用进行了评估。测试了三种不同剂量的替扎尼定（4、8和12毫克），并与150微克可乐定进行比较。12毫克替扎尼定的镇静和抗交感神经作用在程度上与150微克可乐定相当，但可乐定的作用持续时间更长。同样，观察到的动脉血压下降（舒张压，替扎尼定和可乐定分别为13%和19%；收缩压，分别为10%和8%）和唾液分泌减少在程度上相当，但12毫克替扎尼定后的持续时间比可乐定短。可乐定和12毫克替扎尼定对生长激素分泌也有类似作用。我们的结果表明，单次口服剂量12毫克替扎尼定的作用类似于口服150微克可乐定的作用，但持续时间较短。因此，在围手术期，替扎尼定作为一种口服活性、短效α2肾上腺素能受体激动剂，可能是可乐定的一种有用替代品。
