title: Effectivity of Dysport in patients with blepharospasm and hemifacial spasm who experienced failure with Botox.
abstract: BACKGROUND
  Long-term therapy with botulinum toxin is sometimes associated with therapy failure following repeated injections of the neurotoxin, presumably due to specific antibody production. Primary therapy failure with botulinum toxin is less common and poorly understood.
  
  
  OBJECTIVE
  To examine the effectiveness of the botulinum neurotoxin Dysport in patients with blepharospasm and hemifacial spasm after primary or secondary failure with Botox treatments.
  
  
  METHODS
  In this case series study, eight patients with blepharospasm and hemifacial spasm who experienced primary or secondary therapy failure with Botox were treated with Dysport. In order to render an equivalent Dysport dose, a conversion ratio of 1:3 to 1:4 Botox/Dysport was used.
  
  
  RESULTS
  Two patients, one with blepharospasm and the other with hemifacial spasm, who showed primary therapeutic failure with Botox showed good response to Dysport treatments. One patient with tardive blepharospasm did not respond to either drug. Two patients with blepharospasm and three patients with hemifacial spasm who experienced Botox secondary therapy failure responded well to Dysport treatments.
  
  
  CONCLUSIONS
  Botox and Dysport are both serotype A botulinum toxins but carry different characteristics of biological activity. These differences possibly account for the favorable therapeutic response to Dysport in patients with hemifacial spasm or blepharospasm following failure with Botox treatments.
authors.affiliation: Movement Disorders Clinic, Neurology Department, Lady Davis Carmel Medical Center, Haifa, Israel. samihba@clalit.org.il
authors.forename: Samih
authors.initials: S
authors.lastname: Badarny
authors.forename: Zvi
authors.initials: Z
authors.lastname: Susel
authors.forename: Silvia
authors.initials: S
authors.lastname: Honigman