title: Combined use of botulinum toxin type A and B for forehead rhytides: a randomized, double-blind, split-face study.
abstract: BACKGROUND
  This is the first well-controlled study of the combined use of botulinum toxin type A (BoNT-A) and botulinum toxin type B (BoNT-B) for hyperkinetic lines in forehead.
  
  
  OBJECTIVE
  To evaluate the effectiveness and safety of a mixture of BoNT-A and BoNT-B with that of equipotent BoNT-A alone for treating patients with forehead rhytides.
  
  
  METHODS
  Fourteen patients with forehead wrinkles completed this clinical study. On day 0, patients received a mixture of BoNT-A (5 U) and B (500 U) on one side of the forehead and BoNT-A (10 U) symmetrically on the other side. Clinical evaluation was made at the beginning and at weeks 1, 2, 4, 8, 12, and 16. Therapeutic efficacy was evaluated using clinical improvement scale by investigators and the subjective wrinkle assessment by patients.
  
  
  RESULTS
  According to investigator assessment, the differences between the average improvement scores of the two differently treated sides were not statistically significant at all follow-up visits. Moreover, the plateau of the clinical benefit was achieved at week 4.
  
  
  CONCLUSIONS
  We observed the equivalent efficacy in the mixture of both toxins and BoNT-A alone.
authors.affiliation: Department of Dermatology, Seoul National University Bundang Hospital, Seongnam, Gyeonggi-do, Korea.
authors.forename: Jee-Woong
authors.initials: JW
authors.lastname: Choi
authors.forename: Choon-Shik
authors.initials: CS
authors.lastname: Youn
authors.forename: Hi-Tae
authors.initials: HT
authors.lastname: An
authors.forename: Jong-Yeop
authors.initials: JY
authors.lastname: Yoo
authors.forename: Jung-Im
authors.initials: JI
authors.lastname: Na
authors.forename: Kyoung-Chan
authors.initials: KC
authors.lastname: Park
authors.forename: Sang-Woong
authors.initials: SW
authors.lastname: Youn
authors.forename: Chang-Hun
authors.initials: CH
authors.lastname: Huh
mesh_terms: D000328:Adult; D001905:Botulinum Toxins / Q000627:therapeutic use*; D019274:Botulinum Toxins, Type A / Q000627:therapeutic use*; D004311:Double-Blind Method; D004359:Drug Therapy, Combination; D005260:Female; D005546:Forehead; D006801:Humans; D008297:Male; D008875:Middle Aged; D009465:Neuromuscular Agents / Q000627:therapeutic use*; D015595:Skin Aging / Q000187:drug effects*; D016896:Treatment Outcome
chemical_list: D009465:Neuromuscular Agents; C096323:rimabotulinumtoxinB; D001905:Botulinum Toxins; D019274:Botulinum Toxins, Type A; C545476:incobotulinumtoxinA