Background: The determination of the action halos of botulinum toxin type A aids in targeting specific muscles and/or sweat glands, thereby preventing the occurrence of side effects.
Objectives: The objective of this study was to compare the action halos of two commercial preparations of botulinum toxin type A, Dysport (Ipsen, Slough, UK) and BOTOX (Allergan, Irvine, CA).
Material and methods: Eighteen volunteers received applications of both products into randomized sides of the frontalis muscle. Equivalent doses of 5 U of Dysport and 2 U of BOTOX were injected using the same technique, in the same volume (0.02 mL), and at a controlled depth. Twenty-eight days later, clinical and photographic assessments were performed.
Results: All the areas around the injected points were regular, round, or slightly oval and showed similar effects in the muscles and sweat glands. No statistically significant differences were observed between the mean sizes of the diameters of the halos produced by the two products.
Conclusion: Injections of Dysport and BOTOX at an equivalence ratio of 2.5:1 U, respectively, applied at the same volume and depth, using the same technique resulted in similar action halos with regard to muscular and sweat gland activity. Both products seem to be safe and very predictable.