title: The effect of defasciculating doses of pancuronium and atracurium on succinylcholine neuromuscular blockade.
abstract: BACKGROUND
  A defasciculating dose of non-depolarizing muscle relaxant administered prior succinylcholine decrease its side effects including fasciculations and postoperative myalgias; however it is believed that the dosage of succinylcholine should be increased when such a pre-treatment is used.
  
  
  OBJECTIVE
  We hypothesized that a defasciculating dose of pancuronium as a pre-treatment could prolong its duration of effect.
  
  
  METHODS
  Forty patients scheduled for elective orthopaedic surgery were consecutively assigned into 5 groups, a first group without pre-treatment (succinylcholine 1 mg/kg) and 4 subsequent groups of pretreatment with atracurium 0.05 mg/kg + succinylcholine 1 or 1.5 mg/kg and pancuronium 7.5 µg /kg + succinylcholine 1 and 1.5 mg/kg. The muscle relaxant effect of succinylcholine was assessed with a force transducer using train of four stimulations every 12 seconds. Kruskall Wallis Anova test was used to compare results.
  
  
  RESULTS
  The duration of succinylcholine induced paralysis (1 and 1.5 mg/kg) was significantly prolonged with pre-treatment with pancuronium but succinylcholine 1mg/kg did not reached maximum blockade after pre-treatment with atracurium. After pancuronium, full recovery after succinylcholine 1.5 and 1 mg/kg occurred respectively after 18 and 15 minutes. P < 0.05 vs. 12 minutes for succinylcholine 1mg/kg alone.
  
  
  CONCLUSIONS
  This study highlights potentiation effect of a defasciculating dose of pancuronium on succinylcholine paralysis suggesting the lack of justification to increase succinylcholine dosage.
authors.affiliation: Department of Anesthesia, Gustave Roussy Institute, Rue Camille Desmoulins 94080 Villejuif, France University of Paris 11, Paris, France.
authors.forename: Cyrus
authors.initials: C
authors.lastname: Motamed
authors.affiliation: Department of Anesthesia, Hospital Henri Mondor, Avenue de Lattre de Tassigny 94010 Créteil, France University of Paris 12, Paris, France.
authors.forename: Duvaldestin
authors.initials: D
authors.lastname: Philippe
keywords: Atracurium; Pancuronium; Succinylcholine