the safety margin for metabolic toxicity ( ratio between iv doses producing severe metabolic side-effects and doses necessary for deep surgical analgesia ) were calculated for each narcotic and found as follows : 1 for pethidine , 3.3 for piritramide , 13 for morphine and phenoperidine , 12.5 for r 39 209 , 60 for fentanyl , 800 for sufentanil and 4 000 for r 34 995 .
C0015846
fentanyl
C0143993
sufentanil