title: The clinical use of the neuromuscular blocking agent rocuronium in dogs.
abstract: OBJECTIVE
  The aim of this study was to characterize the onset and duration of action of the aminosteroid muscle relaxant rocuronium in dogs under clinical conditions.
  
  
  METHODS
  Prospective single dose trial.
  
  
  METHODS
  Twenty-three dogs aged between 6 months and 12 years, weighing between 5.5 and 61.5 kg admitted to the University of Liverpool Small Animal Hospital between January and March 2000, and undergoing elective surgical procedures under general anaesthesia.
  
  
  METHODS
  Following induction of general anaesthesia, neuromuscular function was evaluated using train-of-four (TOF) stimulation. An initial dose of 0.4 mg kg-1rocuronium was administered intravenously (IV) and neuromuscular blockade was monitored by visually assessing the number of responses (twitches) to TOF stimulation (train-of-four count: TOFC). Incremental doses of 0.16 mg kg-1rocuronium were administered as indicated, when at least two twitches of the TOFC had returned.
  
  
  RESULTS
  Rocuronium (0.4 mg kg-1) abolished all responses to TOF stimulation in all dogs. The mean time to onset of neuromuscular blockade (complete abolition of all twitches) was 98 ± 52 seconds. Neuromuscular blockade (absence of all twitches to return of all four) lasted 32.3 ± 8.2 minutes. Incremental doses of 0.16 mg kg-1had a mean duration of action of 20.8 ± 4.9 minutes and up to seven increments were shown to be noncumulative. The effects of rocuronium were readily antagonized with neostigmine and atropine. Small transient increases in arterial blood pressure, which occurred in three dogs after the administration of rocuronium, were the only cardiovascular side-effects observed.
  
  
  CONCLUSIONS
  Rocuronium is an effective nondepolarizing neuromuscular blocking agent in the dog, with a rapid onset of neuromuscular block after intravenous administration and an intermediate duration of action.
  
  
  CONCLUSIONS
  Rocuronium produced a neuromuscular block with similar characteristics to those obtained with vecuronium, thus apparently offering little advantage over vecuronium. However, its availability in aqueous solution and a longer shelf-life increases convenience.
authors.affiliation: University of Liverpool, Department of Anaesthesia, Liverpool, UK.
authors.forename: Alexandra Ha
authors.initials: AH
authors.lastname: Dugdale
authors.affiliation: University of Liverpool, Department of Anaesthesia, Liverpool, UK.
authors.forename: Wendy A
authors.initials: WA
authors.lastname: Adams
authors.affiliation: University of Liverpool, Department of Anaesthesia, Liverpool, UK.
authors.forename: Ronald S
authors.initials: RS
authors.lastname: Jones
keywords: dogs; neuromuscular blockade; rocuronium