tokens: In patients premedicated with scopolamine + morphine ( + 5 mg nitrazepam the evening before surgery ) , the sleep - inducing effect of midazolam 0 . 15 mg / kg i . v . was clearly slower in onset than that of thiopentone 4 . 67 mg / kg i . v . Somewhat fewer cardiovascular and local sequelae were found in the midazolam group , but , although apnoea occurred less often in the midazolam group it lasted longer .