title: Duration of efficacy increases with the repetition of botulinum toxin A injections in primary palmar hyperhidrosis: a study of 28 patients.
abstract: BACKGROUND
  Intradermal injections of botulinum toxin are effective but transitory in primary palmar hyperhidrosis. These injections are repeated when the symptoms recur. We do not know how the duration of efficacy changes when injections are repeated.
  
  
  OBJECTIVE
  In this retrospective study, we aimed to investigate the change in the duration of efficacy of botulinum toxin A (Dysport, Ipsen, Boulogne-Billancourt, France) with the repetition of injections in patients with primary palmar hyperhidrosis.
  
  
  METHODS
  From May 2001 to April 2012, 28 patients were treated with a dose of 250 U of botulinum toxin A per palm. We compared the duration of efficacy of the first and last toxin injections.
  
  
  RESULTS
  The median duration of efficacy was 7 months for the first injection and 9.5 months for the last, the difference being statistically significant (P = .0002).
  
  
  CONCLUSIONS
  Study limitations include a relatively small number of patients treated at a single center and evaluated retrospectively.
  
  
  CONCLUSIONS
  To our knowledge, this study is the first to report a significant increase in the duration of efficacy of botulinum toxin A injections with the repetition of injections in patients with primary palmar hyperhidrosis. The reasons for this effect may be linked to the mechanism of action of botulinum toxin, and may improve our understanding of its pharmacologic effects.
authors.affiliation: Department of Dermatology, Le Mans Hospital, Le Mans, France. Electronic address: marie.lecouflet@gmail.com.
authors.forename: Marie
authors.initials: M
authors.lastname: Lecouflet
authors.affiliation: Unit of Epidemiology and Biostatistics, Department of Public Health, Nantes University Hospital, Nantes, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Leux
authors.affiliation: Department of Dermatology, Le Mans Hospital, Le Mans, France.
authors.forename: Marion
authors.initials: M
authors.lastname: Fenot
authors.affiliation: Department of Dermatology, Le Mans Hospital, Le Mans, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Célerier
authors.affiliation: Department of Dermatology, Le Mans Hospital, Le Mans, France.
authors.forename: Hervé
authors.initials: H
authors.lastname: Maillard
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001905:Botulinum Toxins / Q000008:administration & dosage*; D015331:Cohort Studies; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006945:Hyperhidrosis / Q000175:diagnosis* / Q000188:drug therapy*; D007271:Injections, Intradermal; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D018570:Risk Assessment; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D001905:Botulinum Toxins
keywords: axillary; botulinum toxin; duration of efficacy; hyperhidrosis; increase; repetition of injections