Urapidil is a new antihypertensive agent known to diminish total peripheral vascular resistance by postsynaptic alpha 1-adrenergic blockade and central sympatholytic activity. The purpose of this study was to determine its effectiveness and safety in preventing hemodynamic responses to endotracheal intubation under general anesthesia.

Thirty normotensive, ASA physical status I patients for elective surgery were selected randomly. They were divided into three groups(Group 1: control group with saline, Group 2: urapidil 0.4 mg/kg, Group 3: urapidil 0.5 mg/kg, n=10 in each group). The drugs were injected 3 minutes before induction with thiopental sodium(4 mg/kg) and succinylcholine(1 mg/kg). Endotracheal intubation was performed 5 minutes after the drugs injection. After endotracheal intubation, vecuronium 0.1 mg/kg was injected and 50% nitrous oxide in oxygen and 2Vol% enflurane were inhaled. We measured the blood pressure and the heart rate with noninvasive method at one minute interval for 5 minutes.

In group 3, no significant increase in systolic blood pressure after endotracheal intubation was noted(p<0.05). Urapidil groups showed increase in heart rate at 1, 2 minutes after urapidil injection(p<0.05) and did not blunt increase in heart rate after endotracheal intubation. The side effects of urapidil(hypotension, dizziness, headache and chest tightness) occured in a patient of group 3.

We found that the blood pressure response was effectively controlled, but the change in heart rate was not controlled by urapidil 0.5 mg/kg injection before induction.