title: Efficacy and safety of botulinum toxin type A in the treatment of lateral crow's feet: double-blind, placebo-controlled, dose-ranging study.
abstract: BACKGROUND
  Botulinum toxin type A (BoNT-A) is frequently used to treat crow's feet; the optimal dose for each toxin preparation should be established.
  
  
  OBJECTIVE
  To compare the efficacy and safety of three doses of BoNT-A with placebo to treat crow's feet.
  
  
  METHODS
  Subjects with moderate to severe crow's feet at maximum smile (mild to severe at rest) were randomized to a single bilateral BoNT-A treatment (15, 30, or 45 U) or placebo. Outcome measures included evaluation of crow's feet by an independent panel from blinded photographs at maximum smile, investigator assessment, and patient satisfaction.
  
  
  RESULTS
  Independent panel assessments (Week 4) showed that all BoNT-A doses resulted in significant improvements in crow's feet severity at maximum smile (p<.001); a clear dose-response effect was seen. Improvement over placebo was seen in the 30-U and 45-U groups to Week 12. Investigator assessment showed significant improvement for all doses for 12 weeks at maximum smile and rest (p< or =.01). Patient satisfaction was significantly greater for all doses than for placebo for 16 weeks (all p<.05). All doses were well tolerated. CONCLUSION BoNT-A (15, 30, or 45 U) is an effective and safe treatment for mild to severe crow's feet.
authors.affiliation: Clinique Iena, Paris, France. benjaminascher@wanadoo.fr
authors.forename: Benjamin
authors.initials: B
authors.lastname: Ascher
authors.forename: Berthold J
authors.initials: BJ
authors.lastname: Rzany
authors.forename: Rajiv
authors.initials: R
authors.lastname: Grover
mesh_terms: D000328:Adult; D000368:Aged; D019274:Botulinum Toxins, Type A / Q000008:administration & dosage*; D003357:Cosmetic Techniques; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005123:Eye; D005260:Female; D006801:Humans; D007279:Injections, Subcutaneous; D008297:Male; D008875:Middle Aged; D009465:Neuromuscular Agents / Q000008:administration & dosage*; D015595:Skin Aging / Q000187:drug effects*; D016896:Treatment Outcome
chemical_list: D009465:Neuromuscular Agents; D019274:Botulinum Toxins, Type A