title: Reduction in injection pain with botulinum toxin type B further diluted using saline with preservative: a double-blind, randomized controlled trial.
abstract: BACKGROUND
  Injection with botulinum A exotoxin reconstituted with preserved saline has been shown to be less uncomfortable than injection with the same toxin reconstituted with preservative-free saline.
  
  
  OBJECTIVE
  We sought to determine whether injection with botulinum toxin type B is similarly less painful when preservative-containing saline is used to further dilute the product.
  
  
  METHODS
  We conducted a double-blind, randomized controlled trial. A total of 15 consecutive adult patients presenting for treatment of upper face dynamic lines received treatment to one side (left or right) of the face with toxin type B further diluted with preservative-containing saline, and to the other side with toxin type B further diluted with preservative-free saline.
  
  
  RESULTS
  Of 15 patients, 13 (87%) reported less pain in the halves of their faces treated with the preservative-containing saline (P =.0006). Pain on the preservative-containing side was on average 32% less among patients as a whole, and 39% less among patients noting some reduction. The 95% confidence interval for pain reduction associated with preservative-containing injection was -46.9% to -16.1%. Neither investigators nor patients observed any difference in clinical efficacy between the 2 treatment sides.
  
  
  CONCLUSIONS
  Use of preservative-containing saline to further dilute botulinum toxin type B can significantly decrease patient discomfort on injection.
authors.affiliation: SkinCare Physicians of Chestnut Hill, Chestnut Hill, MA 02467, USA.
authors.forename: S
authors.initials: S
authors.lastname: van Laborde
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Dover
authors.forename: Megan
authors.initials: M
authors.lastname: Moore
authors.forename: Brigitte
authors.initials: B
authors.lastname: Stewart
authors.forename: Kenneth A
authors.initials: KA
authors.lastname: Arndt
authors.forename: Murad
authors.initials: M
authors.lastname: Alam
mesh_terms: D001905:Botulinum Toxins / Q000008:administration & dosage*; D019274:Botulinum Toxins, Type A; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007267:Injections / Q000009:adverse effects; D008297:Male; D008666:Metalloendopeptidases / Q000008:administration & dosage*; D008875:Middle Aged; D010146:Pain / Q000517:prevention & control; D011310:Preservatives, Pharmaceutical; D011446:Prospective Studies; D012965:Sodium Chloride
chemical_list: D011310:Preservatives, Pharmaceutical; C096323:rimabotulinumtoxinB; D012965:Sodium Chloride; D008666:Metalloendopeptidases; D001905:Botulinum Toxins; D019274:Botulinum Toxins, Type A