POTENTIATION OF THE NEUROMUSCULAR BLOCKADE PRODUCED BY ALCURONIUM WITH HALOTHANE, ENFLURANE AND ISOFLURANE

The potentiation of alcuronium by halothane, enflurane and isofluranewas investigated using electromyography. In the first study,cumulative dose-response curves were constructed in four groupsof 10 patients anaesthetized with one of the inhalation agentsand nitrous oxide, or with fentanyl and droperidol (control).All three agents reduced the ED₅₀ of alcuronium; the effectwas marked with isoflurane (P < 0.005) but less so with halothane(P < 0.05) and enflurane (ns). In the second part of theinvestigation, designed primarily to test the duration of actionof alcuronium with each agent, a single bolus dose of alcuronium0.2 mg kg^–1 was given to four similar groups (n = 5).The duration of action was significantly prolonged by enflurane(P < 0.01) and isoflurane (P < 0.05), but not by halothane.The possible reasons for this are discussed.