Botulinum toxin A is used in aesthetic medicine for the treatment of wrinkles. It is a neurotoxin whose mechanism of action is based on inhibiting the transmission of excitation from nerve cells to other cells, especially muscle cells.
By destroying protein complexes, the release of the neurotransmitter acetylcholine is blocked depending on the target tissue, because of which the contraction of the muscle becomes weaker or fails completely, causing paralysis of the muscle. The duration of action of the substance usually lasts up to 12 weeks.
Low-dose botulinum toxin A is particularly suitable for the treatment of dynamic facial wrinkles in the upper third of the face and neck, which are caused by activity of the mimic muscles. Dosages of up to 100 units of Botox and 230 units of Dysport per session are used to correct wrinkles.
On average, the dosage of Botox is 20 to 40 units and of Dysport 100 units, so if performed correctly, there are usually no serious side effects. The lethal dose of botulinum toxin A for a 70kg person is 3000 units.
In one study, J. Kaufman-Janette et al (2021) looked at higher doses of botulinum toxin A for injections into the glabellar folds. This involved 5 studies that were randomized, double-blinded, and with varying population sizes.
Botulinum toxin formulations approved for the treatment of glabellar wrinkles in the USA or in Europe (Abotulinumtoxin A, Incobotulinumtoxin A, Onabotulinumtoxin A) were used. A high dosage was defined as a dosage that was higher than the dosage indicated in the technical information of the respective formulations.
The result of the study illustrates that an injection with a higher dosage of the botulinum toxin A drug is applicable and increases the duration of action of the drug without increasing potential risks.
An approximately 9-month increase in duration of action was obtained with a 2-2.5-fold increase in the on-label dose of Abotulinumtoxin A or a 5-fold increase in Incobotulinumtoxin A. A median duration of action of approximately 6 months was achieved with a 2-4-fold increase in the on-label dose of Onabotulinumtoxin A.
The goal of treatment with increased botulinum toxin A dosage is to ensure patient satisfaction and to achieve a natural appearance. Although more data need to be collected, the findings of this study may contribute to more effective treatment and an individualized treatment plan to meet patient expectations.
Kerscher, Martina et al.: Botulinumtoxin A in der Faltenbehandlung: Übersicht und Abgrenzung zu alternativen Verfahren Dtsch Arztebl 2001; 98(26): A-1758 / B-1508 / C-1400
J. Schantz, E. A. Johnson: Properties and use of botulinum toxin and other microbial neurotoxins in medicine. In: Microbiol Rev.1992;56, S. 80–99.