Interaction of ORG 9426 and some of the clinically used intravenous anaesthetic agents in the cat.

The interaction of ORG 9426, a new non-depolarizing neuromuscular blocking agent, with intravenous anaesthetic drugs (fentanyl, thiopental, midazolam, droperidol and etomidate) has been investigated in cats. During an infusion of one of the above anaesthetics, the ED95 dose was determined by titration, and thereafter muscle relaxation was maintained with four subsequent doses of ORG 9426. Neither the potency nor the duration of action of the first dose nor that of the maintenance doses of ORG 9426 differed from those observed in a control group of cats anaesthetized with intraperitoneally administered pentobarbital. The recovery rates were similar in all groups. The authors conclude that, under the conditions of this study, commonly used intravenous anaesthetic drugs are not likely to influence the neuromuscular blocking potency and time course of action of ORG 9426 to any appreciable degree.