title: Dose-ranging study of botulinum toxin type A in the treatment of glabellar rhytids in females.
abstract: OBJECTIVE
  To compare the efficacy, safety, and duration of effect of four doses of botulinum toxin type A in the treatment of glabellar rhytids in females.
  
  
  METHODS
  Double-blind, randomized, parallel-group, dose-ranging trial followed by an open-label extension.
  
  
  METHODS
  Private dermatologic clinic.
  
  
  METHODS
  Eighty female subjects with moderate to severe wrinkles at maximum frown entered the study. The first 40 subjects completing the double-blind phase entered the open-label extension.
  
  
  METHODS
  Random administration of 10, 20, 30, or 40 U botulinum toxin type A in divided doses. Open-label trial: 30 U botulinum toxin type A at the same sites in divided doses.
  
  
  METHODS
  Trained observer and subject assessments of wrinkle severity at maximum frown and repose using the Facial Wrinkle Scale (0 = none to 3 = severe), subject satisfaction, and adverse events. Follow-up monthly for up to 1 year postinjection.
  
  
  RESULTS
  Relapse rates and responder rates revealed benefits lasting 3 to 6 months or longer. Objectively, 10 U of botulinum toxin type A was significantly less effective than 20, 30, or 40 U. The relapse rate at 4 months was significantly higher in the 10 U group (83%) versus 40, 30, or 20 U (28%, 30%, and 33%, respectively). Subject satisfaction was high in all groups. Duration of effect and response rates were sustained during the open-label extension. Adverse effects were mild and infrequent.
  
  
  CONCLUSIONS
  Twenty to 40 U botulinum toxin type A doses were significantly more effective at reducing glabellar lines than 10 U. Most subjects experienced benefits for 3 to 4 months; some subjects demonstrated effect for up to 12 months.
authors.affiliation: University of British Columbia, Vancouver, British Columbia, Canada. alastair@carruthers.net
authors.forename: Alastair
authors.initials: A
authors.lastname: Carruthers
authors.forename: Jean
authors.initials: J
authors.lastname: Carruthers
authors.forename: Samireh
authors.initials: S
authors.lastname: Said
mesh_terms: D000293:Adolescent; D000328:Adult; D019274:Botulinum Toxins, Type A / Q000008:administration & dosage* / Q000009:adverse effects; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D005546:Forehead; D006801:Humans; D008875:Middle Aged; D009465:Neuromuscular Agents / Q000008:administration & dosage* / Q000009:adverse effects; D015361:Rhytidoplasty; D015595:Skin Aging / Q000187:drug effects*; D016896:Treatment Outcome
chemical_list: D009465:Neuromuscular Agents; D019274:Botulinum Toxins, Type A