title: Evolution of dose and response to botulinum toxin A in cervical dystonia: a multicenter study.
abstract: Botulinum neurotoxin (BoNT) is an effective treatment for cervical dystonia (CD). Long-term changes of several variables, including the dose of BoNT, in these patients is largely unknown. We reviewed the clinical charts of 275 patients with CD treated with BoNT type A (BoNT-A) for at least 5 years since 1989 at ten tertiary centers. The mean dose of BoNT-A per session during the first 5 years of treatment was calculated and the appearance of resistance was noted. The dose of BoNT-A for the whole group showed a significant trend to increase over time (year 1: 180 ± 65 U; year 5: 203 ± 63 U; ANOVA: p < 0.0001). However, when we studied the evolution of the dose of BoNT-A for those patients (n = 49) first injected after 2000 (introduction of current BOTOX preparation in our country), there was no significant increase in dose (year 1: 181.8 ± 75 U; year 5: 181.7 ± 75 U; ANOVA p: ns). A total of 19 patients became secondary nonresponders; all but one of these patients began BoNT-A treatment before 2000. In summary, there is a statistically significant increase of mean dose of BoNT-A per session over time, and this could be explained by the appearance of secondary nonresponders. On the other hand, those patients initially treated after 2000 did not show any statistically significant increase in dose for 5 years. This could be explained by better experience and techniques, fewer immunogenic problems with the current BoNT-A, and also less variability of the dose per vial.
authors.affiliation: Department of Neurology, Fundación Jiménez Díaz, Madrid, Spain.
authors.forename: Pedro J Garcia
authors.initials: PJ
authors.lastname: Ruiz
authors.forename: Juan Carlos Martínez
authors.initials: JC
authors.lastname: Castrillo
authors.forename: Juan A
authors.initials: JA
authors.lastname: Burguera
authors.forename: Victor
authors.initials: V
authors.lastname: Campos
authors.forename: Alfonso
authors.initials: A
authors.lastname: Castro
authors.forename: Esther
authors.initials: E
authors.lastname: Cancho
authors.forename: Jose
authors.initials: J
authors.lastname: Chacón
authors.forename: Jaime Hernández
authors.initials: JH
authors.lastname: Vara
authors.forename: Javier Lopez
authors.initials: JL
authors.lastname: del Val
authors.forename: Elena Lopez
authors.initials: EL
authors.lastname: Garcia
authors.forename: Francesc
authors.initials: F
authors.lastname: Miquel
authors.forename: Pilar
authors.initials: P
authors.lastname: Sanz
authors.forename: Lydia
authors.initials: L
authors.lastname: Vela
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D019274:Botulinum Toxins, Type A / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009465:Neuromuscular Agents / Q000627:therapeutic use*; D012189:Retrospective Studies; D014103:Torticollis / Q000188:drug therapy*; D016896:Treatment Outcome
chemical_list: D009465:Neuromuscular Agents; D019274:Botulinum Toxins, Type A