title: Effect of alfentanil on hypnotic and antinociceptive components of thiopental sodium anesthesia.
abstract: OBJECTIVE
  To determine the effects of alfentanil on the hypnotic and antinociceptive components of thiopental sodium anesthesia.
  
  
  METHODS
  Randomized double-blind study.
  
  
  METHODS
  Inpatients at a university-affiliated county hospital.
  
  
  METHODS
  Eighty unpremedicated ASA physical status I or II female patients aged 18 to 60 years, with a weight range of 50 to 90 kg.
  
  
  METHODS
  Intravenous injection of thiopental sodium in doses ranging from 1.0 mg/kg to 6.0 mg/kg with or without the addition of alfentanil, 0.01 mg/kg.
  
  
  RESULTS
  Dose-response curves were determined for the following three endpoints of anesthesia: eye opening in the response to voice command; eye opening in the response to noxious stimulation induced by pressure on the trapezius muscle; and purposeful movement in the response to the same type of noxious stimulation. The addition of alfentanil, 0.01 mg/kg, markedly decreased thiopental ED50 values for all three endpoints: from 2.6 mg/kg to 1.9 mg/kg (p less than 0.02) for eye opening to voice command, from 3.2 mg/kg to 1.9 mg/kg (p less than 0.0005) for eye opening to noxious pressure, and from 4.2 mg/kg to 2.4 mg/kg (p less than 0.0001) for purposeful movement to noxious pressure. The alfentanil-induced increase in thiopental potency for the antinociceptive effect was greater than that for the hypnotic effect (75% vs 36%, p = 0.02).
  
  
  CONCLUSIONS
  Alfentanil strengthened both the hypnotic and antinociceptive components of thiopental anesthesia, although to a different degree: the antinociceptive component more so than the hypnotic, possibly because each component of anesthesia has different underlying mechanisms.
authors.affiliation: Department of Anesthesiology, School of Medicine, University of Alabama, Birmingham 35294.
authors.forename: D
authors.initials: D
authors.lastname: Mehta
authors.forename: E L
authors.initials: EL
authors.lastname: Bradley
authors.forename: I
authors.initials: I
authors.lastname: Kissin
mesh_terms: D000328:Adult; D015760:Alfentanil; D000771:Anesthesia, Intravenous; D004311:Double-Blind Method; D004357:Drug Synergism; D005260:Female; D006801:Humans; D008875:Middle Aged; D013874:Thiopental
chemical_list: D015760:Alfentanil; D013874:Thiopental