Fields of muscular and anhidrotic effects of 2 botulinum toxin-A commercial preparations: a prospective, double-blind, randomized, multicenter study.

Background: Longevity of effects and dose equivalence of different botulinum toxin type A (BoNT-A) preparations need to be better clarified because BoNT-A units are manufacturer-specific. These points are of particular importance for new brands emerging in the market.

Objective: To assess the field of muscular and anhidrotic effects of 2 commercial preparations of BoNT-A (incobotulinumtoxinA: Xeomin [XEO]; abobotulinumtoxinA: Dysport [DYS]) administered to the upper third of the face.

Methods: Patients were randomized for the side of the forehead (left or right) in which the products were administered. All were treated receiving BoNT-A injections in 10 points (5 on each side) at a dose equivalence of 1.0:2.5 U (XEO:DYS). Clinical assessments and Minor test were performed at baseline and Days 28, 84, 112, and 140. Electromyography was performed at baseline and Days 28 and 140, and ultrasound was performed only at baseline.

Results: Eighty patients were enrolled in 2 research centers. Xeomin and DYS presented similar results regarding fields of muscular effects. However, a larger field of anhidrotic effects was found for DYS. There was a positive correlation between the muscle thickness and electromyography results.

Conclusion: The results of this study suggest that a lower dose equivalence between DYS and XEO could be established.