title: Retrospective evaluation of the dose equivalence of Botox(®) and Dysport          (®) in the management of blepharospasm and hemifacial spasm: a novel paradigm for a never ending story.
abstract: Botox(®) and Dysport(®) are the preparations of botulinum neurotoxin most widely used for therapeutic purposes. Several studies have addressed the topic of the equivalency ratio (D/B ratio) to be used in clinical practice and whether a reliable value exists is still a matter of debate. To this purpose, we ideated a novel paradigm by retrospectively examining the patients affected by hemifacial spasm and blepharospasm. We compared the pairs of treatments with a switch from one brand to the other undergone by the same patient in consecutive sessions with overlapping clinical outcome. Out of 2006 treatments, we found 51 treatment pairs. D/B ratio was extremely variable (range 1.2-13.3) and in most cases (65%) it was between 1:3 and 1:5. In conclusion, even if the 1:4 ratio might be reliable for clinical purpose, a true bioequivalence between Dysport(®) and Botox(®) might not exist due to the intrinsic difference in their pharmacokinetic properties.
authors.affiliation: Istituto di Neurologia, Università Cattolica del Sacro Cuore, Largo Agostino Gemelli, 8, 00168 Rome, Italy.
authors.forename: Anna Rita
authors.initials: AR
authors.lastname: Bentivoglio
authors.forename: Tàmara
authors.initials: T
authors.lastname: Ialongo
authors.forename: Francesco
authors.initials: F
authors.lastname: Bove
authors.forename: Francesca
authors.initials: F
authors.lastname: De Nigris
authors.forename: Alfonso
authors.initials: A
authors.lastname: Fasano
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001764:Blepharospasm / Q000188:drug therapy*; D019274:Botulinum Toxins, Type A / Q000627:therapeutic use*; D005260:Female; D019569:Hemifacial Spasm / Q000188:drug therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D016896:Treatment Outcome
chemical_list: D019274:Botulinum Toxins, Type A; C542869:abobotulinumtoxinA