Abstract: AIM: To investigate the effect ofPremedication with clonidine on the concentrations of catecholamine(CA),angiotentionⅡ(AⅡ),cortisol and carbohydrate metabolism during tracheal extubation.METHODS: Twenty-twoPatients scheduled for general anesthesia with tracheal intubation were randomly divided into two groups:clonidine grouPand control group.OralPremedication with clonidine 5μg·kg^-1was taken in clonidine grouP60 min before anesthesia induction in addition to some commonPremedication in both groups.The change of hemodynamics,arterialPlasma concentrations of CA,AⅡ,cortisol,blood sugar andlactic acid were measured before anesthesia,before intubation and 1,2,5,10 min after tracheal extubation,respectively.RESULTS: Thelevels of CA,AⅡ,cotisol,blood sugar andlactic acid were significantly increased during tracheal extubation in both groups,but thelevels in control grouPwere higher than those in clonidine group.The change of hemodynamics was more stable in clonidine grouPthan that in control group.CONCLUSION: OralPremedication with clonidine can alleviate stress response during tracheal extubation.

Key words: pharmacodynamics, tracheal extubation, stress, clonidine, premedication