title: Onabotulinum toxin A dosage trends over time for adductor spasmodic dysphonia: A 15-year experience.
abstract: OBJECTIVE
  Although onabotulinum neurotoxin A (BoNTA) has been used for over three decades for the treatment of adductor spasmodic dysphonia, no study has been performed to look at the trend of BoNTA dosages across time. The goal of this study is to evaluate the dosage trends to determine if the dosage necessary for voice improvement in patients increases over time.
  
  
  METHODS
  Charts were reviewed for patients with 15 years or more of experience.
  
  
  METHODS
  Linear regression analysis was performed to determine correlation coefficients and trends.
  
  
  RESULTS
  Fifty-five patients receiving BoNTA injections by the senior author (a.b.) for over 15 years were evaluated. Thirty-nine patients (82% female) met inclusion criteria. Patients received injections over an average of 18.6 years ± 1.36 years, with the longest follow-up of 21.5 years. Of 39 patients, 16 (41%) had a negative correlation coefficient (Pearson's r) suggesting a decrease over time, whereas 23 (59%) had a positive correlation coefficient suggesting an increase over time. The mean correlation coefficient was 0.139 ± 0.534 and P < 0.05 in 19 patients and P > 0.05 in 20 patients. R(2) for all patients were less than 0.75.
  
  
  CONCLUSIONS
  Onabotulinum neurotoxin A injection dosage trends vary depending on the individual over time. Overall, the dose range appears to be stable in the majority of patients, suggesting that tolerance does not play a significant part in dose variation over time.
  
  
  METHODS
  4. Laryngoscope, 126:678-681, 2016.
authors: New York Center for Voice and Swallowing Disorders, New York, New York, U.S.A.
authors: Christopher G
authors: CG
authors: Tang
authors: Sydney Medical School, University of Sydney, Sydney, Australia.
authors: Daniel
authors: D
authors: Novakovic
authors: New York Center for Voice and Swallowing Disorders, New York, New York, U.S.A.
authors: Niv
authors: N
authors: Mor
authors: New York Center for Voice and Swallowing Disorders, New York, New York, U.S.A.
authors: Andrew
authors: A
authors: Blitzer
mesh_terms: D000328:Adult; D019274:Botulinum Toxins, Type A / Q000008:administration & dosage*; D015331:Cohort Studies; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D055154:Dysphonia / Q000175:diagnosis / Q000188:drug therapy*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015552:Injections, Intralesional; D008297:Male; D008875:Middle Aged; D009465:Neuromuscular Agents / Q000008:administration & dosage*; D012189:Retrospective Studies; D018570:Risk Assessment; D012720:Severity of Illness Index; D013997:Time Factors; D016896:Treatment Outcome; D014833:Voice Quality / Q000187:drug effects*; D055815:Young Adult
chemical_list: D009465:Neuromuscular Agents; D019274:Botulinum Toxins, Type A
keywords: Botox; Spasmodic dysphonia; onabotulinum toxin; voice