Article Text

Download PDFPDF
Respective potencies of Botox and Dysport: a double blind, randomised, crossover study in cervical dystonia
  1. D Ranoux1,
  2. C Gury2,
  3. J Fondarai3,
  4. J L Mas1,
  5. M Zuber1
  1. 1Service de Neurologie, Hôf.pital Sainte-Anne, Paris, France
  2. 2Pharmacie, Hôf.pital Sainte-Anne, Paris, France
  3. 3Département de statistiques, Hôf.pital Salvator, Marseille, France
  1. Correspondence to:
 Dr D Ranoux, Service de Neurologie, Hô;f.pital Sainte-Anne, 1 rue Cabanis, 75 674 Paris Cedex 14, France;


Objectives: Botulinum toxin type A is a potent neuromuscular paralyzing agent used in various disorders including cervical dystonia. Two preparations of botulinum toxin are now commercially available ( Dysport and Botox), but much controversy remains about their respective potencies. The aim of the study was to compare the efficacy of Botox with two different ratios of Dysport.

Methods: A double blind, randomised, three period cross over study involving 54 patients with cervical dystonia was performed. The patients received the following treatments in a randomised order: Botox at the usually effective dose, Dysport at a dose of 1:3 (conversion factor of 3 between Botox and Dysport units—that is, one Botox unit=three Dysport units) and at a dose of 1:4 (conversion factor of four). The improvement of the Tsui (primary outcome criteria) and of the TWSTRS pain scales between baseline and a control visit 1 month after each of the three injections, as well as the incidence of adverse events, were assessed.

Results: Comparison of the Tsui scores and of the TWSTRS pain scores showed a better effect on impairment and pain with Dysport 1:3 (p=0.02 and 0.04, respectively) and 1:4 (p=0.01 and 0.02, respectively) than with Botox. The number of adverse events was higher with both Dysport treatments. The most frequent adverse event was dysphagia, found in 3%, 15.6%, and 17.3% (Botox, Dysport 1:3 and 1:4, respectively) of the patients. No adverse event required withdrawal of therapy or specific management.

Conclusions: Dysport 1:3 (and Dysport 1:4 to a greater extent) is more efficient than Botox for both impairment and pain in cervical dystonia although with a somewhat higher incidence of minor adverse effects. This strongly suggests that the most appropriate conversion factor between Botox and Dysport units is less than 3 in cervical dystonia.

  • botulinum toxin
  • cervical dystonia
  • equivalence
  • TWSTRS, Toronto western spasmodic torticollis rating scale

Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.