The effects of benzodiazepines as anaesthesia inducing agents on plasma cortisol level in elective hysterectomy.

The effects of anaesthesia inducing benzodiazepines (diazepam, flunitrazepam, midazolam) on serum cortisol level, blood pressure and pulse rate were examined in patients undergoing elective hysterectomy. Diurnal variation of serum cortisol was established two days before operation. Either form of benzodiazepine provided good suppression of the cortisol response to stress during anaesthesia and surgery. The endocrine response to surgical stress was more pronounced at end of the operation in all three groups. Considering the relative changes of cortisol compared to the pre-operative values the smallest differences were seen in the group receiving midazolam. At 6 p.m. on the day of operation the cortisol level decreased in the flunitrazepam and midazolam groups. Especially in the patients who received midazolam at 6 a.m. on the following day the values did not differ from those observed in the control group. On the basis of these examinations it would appear that to prevent adverse stress-induced effects there is a slight advantage in using midazolam for induction of anaesthesia.