BACKGROUND: Tracheal extubation provokes hypertension and tachycardia, as does tracheal intubation. Especially hypertensive patients are more likely to exhibit substantial fluctuations in hemodynamics and myocardial ischemia than normotensive patients during these stressful periods. The aim of present study was to evaluate the effects of intravenous diltiazem in attenuating mean arterial pressure(MAP) and heart rate(HR) responses to tracheal extubation in hypertensive patients. METHODS: Thirty-seven hypertensive patients who were to undergo elective surgery were randomly assigned to one of three groups : saline (control), lidocaine 1 mg/kg, and diltiazem 0.2 mg/kg. These drugs were given 2 minutes prior to tracheal extubation. Anesthesia was induced by the injection of fentanyl 1.5 microgram/kg, thiopental 5 mg/kg, and vecuronium 0.1 mg/kg and maintained with 50% N2O in O2 and 1~2 vol.% enflurane. Changes in HR and MAP were measured during and after tracheal extubation. RESULTS: In the diltiazem group, the MAP decreased significantly at drug administration, extubation, and post-extubation 1 min. However there were no significant differences in HR among 3 groups. CONCLUSIONS: These data suggest that intravenous injection of diltiazem 0.2 mg/kg given 2 minutes before tracheal extubation was effective in attenuating MAP changes associated with tracheal extubation. But HR changes were not different significantly among 3 groups. Further studies are required for the effective prophylaxis against tachycardia associated with tracheal extubation.