title: Single-center, double-blind, randomized study to evaluate the efficacy of 4% lidocaine cream versus vehicle cream during botulinum toxin type A treatments.
abstract: BACKGROUND
  Botulinum toxin type A (BTX-A) injections are overwhelmingly safe and effective treatment in cosmetic treatment, but some patients are apprehensive about pain associated with injection.
  
  
  OBJECTIVE
  To determine whether preprocedural application of lidocaine 4% topical anesthetic cream to the injection site will reduce pain on injection of BTX-A for the treatment of crow's feet.
  
  
  METHODS
  Twenty-four participants receiving bilateral injections for crow's feet were enrolled. Subjects were randomized to one of four study groups. Prior to BTX-A injection, group 1 (n = 6) received lidocaine 4% cream on the right side of the face and vehicle cream on the left side of the face; group 2 (n = 6) received vehicle cream on the right side and lidocaine 4% on the left side; group 3 (n = 6) received lidocaine 4% on both sides; and group 4 (n = 6) received vehicle cream on both sides.
  
  
  RESULTS
  We observed a statistically significant reduction in subject-reported procedural pain in participants pretreated with lidocaine 4% on both sides of the face compared with controls.
  
  
  CONCLUSIONS
  Lidocaine 4% cream is effective in reducing the pain associated with BTX-A injection for crow's feet. We encourage further study to clarify the optimal use of topical anesthetics in the practice of cosmetic dermatology.
authors.affiliation: Division of Dermatology, University of British Columbia, Vancouver, BC. alastair@carruthers.net
authors.forename: Alastair
authors.initials: A
authors.lastname: Carruthers
authors.forename: Jean
authors.initials: J
authors.lastname: Carruthers
mesh_terms: D000287:Administration, Topical; D000328:Adult; D000779:Anesthetics, Local; D019274:Botulinum Toxins, Type A / Q000009:adverse effects; D004311:Double-Blind Method; D004643:Emollients; D005260:Female; D006801:Humans; D007271:Injections, Intradermal / Q000009:adverse effects*; D008012:Lidocaine; D008297:Male; D008875:Middle Aged; D009465:Neuromuscular Agents / Q000009:adverse effects; D010146:Pain / Q000209:etiology / Q000517:prevention & control*; D014677:Pharmaceutical Vehicles; D016896:Treatment Outcome
chemical_list: D000779:Anesthetics, Local; D004643:Emollients; D009465:Neuromuscular Agents; D014677:Pharmaceutical Vehicles; D008012:Lidocaine; D019274:Botulinum Toxins, Type A