the magnitude and duration of analgesia and respiratory depression induced by fentanyl ( 1.0 , 2.0 , and 4.0 micrograms/kg ) and sufentanil ( 0.1 , 0.2 , and 0.4 microgram/kg ) after intravenous administration over 30 s were measured in 30 healthy young adult male volunteers divided into three groups and studied in a double-blind , randomized fashion .
C0015846
fentanyl
C0143993
sufentanil