[Comparative clinical studies on vecuronium, atracurium and pancuronium in older patients]

The relaxants vecuronium (Norcuron), atracurium (Tracrium), and pancuronium (Pavulon) have been investigated with respect to onset and duration of action in old patients compared with young patients. A variant of a balanced anaesthesia technique with flunitrazepam, fentanyl and N2O/O2 was used. The following equipotent doses were investigated (mg/kg body weight): vecuronium 0.07/0.10; atracurium 0.35/0.50; pancuronium 0.08/0.115. The neuromuscular function was assessed in a semiquantitative manner with the Train-of-Four (TOF). We found a trend to a delayed onset of action in old patients. This effect, however, reached a significant level with pancuronium only. The degree of relaxation after comparable doses was less after atracurium in old patients. This difference between young and old patients could not be observed after vecuronium and was hardly detectable after pancuronium. The duration of action to a 25% recovery and the early recovery phase from the appearance of the first to the fourth twitch in the TOF showed no difference between young and old patients. It is concluded that there are no considerable differences with respect to the duration of action between young and old patients. However, to obtain a similar degree of relaxation, it is recommended to use a somewhat higher dose level with atracurium.