The effect of diazepam on induction of anesthesia with alfentanil

This study investigated the effect of intravenous diazepam on induction of anesthesia with alfentanil. Forty ASA physical status I and II patients were given one of four treatments: alfentanil 100 micrograms/kg or 200 micrograms/kg, without diazepam or preceded by 0.125 mg/kg diazepam intravenously. Blood pressure, heart rate, respiration, response to verbal command, and movement were assessed for 5 min, and blood was taken for measurement of histamine, epinephrine, and norepinephrine. All ten patients receiving 100 micrograms/kg and five of the ten patients receiving 200 micrograms/kg of alfentanil responded to voice after 5 min, but only one in each group responded when it was preceded by diazepam. There was no rigidity or serious arrhythmias in any patient. Heart rate increased in patients receiving alfentanil alone. Blood pressure increased in those receiving 100 micrograms/kg but not 200 micrograms/kg. In patients given diazepam, tachycardia did not occur, but blood pressure decreased after administration of alfentanil. There were no significant changes in plasma levels of histamine or catecholamines. Five of the six cases of inadequate postoperative ventilation were in patients given diazepam. Despite these effects, diazepam or some other hypnotic agent may be indicated when alfentanil is used for induction.