##submission.abstract##
Background: Endotracheal extubation is almost always associated with haemodynamic changes. This increase in sympathoadrenal activity may result in hypertension, tachycardia and arrhythmias and is more hazardous to the patients with hypertension, myocardial insufficiency or cerebrovascular disease. The aim of this randomized double blind study was to compare the effect of diltiazem and esmolol in attenuating  thecardiovascular responses to tracheal extubation.Methods: Changes in heart rate(HR), systolic blood pressure(SBP), diastolic blood pressure(DBP) and mean arteial blood pressure(MAP) were measured during extubation and emergence from anaesthesia in 150 ASA physical status I patients to assess the effect of esmolol and diltiazem.The patients were randomly assigned to one of three groups (n=50 for each group): saline 10ml(as control), 0.1mg/kg diltazem and 1mg/kg esmolol.The medications were given  3 minutes after reversal and 2 min before tracheal extubation.Results:Bothesmolol and diltiazem had greater attenuating effects on changes of  HR, SBP and DBP than control group.The inhibitory effects on changes of heart rate was greater with esmolol than diltiazem, but the attenuating effect on changes of SBP and DBP was greater with diltiazem than esmolol. Conclusion:We concluded that a bolus dose of intravenous diltiazem 0.1mg/kg or esmolol 1mg/kg given at 2 min before extubation was of value in attenuating the cardiovascular changes occuring in association with tracheal extubation.Esmolol is more effective than diltiazem in attenuating the heart rate changes.Diltiazem is more effective than esmolol in attenuating the systolic blood pressure changes.