The mechanisms of action and use of botulinum neurotoxin type A in aesthetics: Key Clinical Postulates II. (16th September 2020)

• Record Type: Journal Article
• Authors: Nestor, Mark S.; Arnold, David; Fischer, Daniel
• Is Part Of: Journal of cosmetic dermatology. Volume 19:Number 11(2020)
• Page Start: 2785
• Page End: 2804
• Publication Date: 2020-09-16
• Subjects: BoNT‐A -- botulinum neurotoxin type A -- key clinical postulates -- molecular potency -- review; Skin -- Diseases -- Treatment -- Periodicals; Lasers in surgery -- Periodicals; Skin -- Pathophysiology -- Periodicals; Surgery, Plastic -- Periodicals; 616.5
• DOI: 10.1111/jocd.13702
• Languages: English
• ISSNs: 1473-2130

Abstract

Abstract: Background: The literature on botulinum neurotoxin type A (BoNT‐A) is extensive, often contradictory, and confounded by a competitive market of products and research attempting to distinguish brand individuality. Methods: A comprehensive review of literature on the principles of BoNT‐A in aesthetics as well as clinical examples. Results: In 2017, the Eight Key Clinical Postulates were formulated as a guide for the aesthetic practitioner in understanding BoNT‐A pharmacodynamics and to compare different toxins. These are now updated to include (a) All type A toxins act identically; (b) The mathematical relationship between toxin and receptor is the basis of efficacy, and clinical efficacy is influenced by molecular potency and patient attributes including muscle mass, gender, age, and ethnicity; (c) Efficacy, onset, and duration are functions of "molecular potency" defined as the number of active 150 kDa molecules available for binding; (d) "Molecular potency" is difficult to objectively quantify for commercially available toxins; (e) Up to a point, increased molecular potency decreases time to onset and increases duration of effect, and the "Molecular Potency Quotient" is a construct for comparing molecular potency commercial cost; (f) The area of effect of a toxin injection is dependent upon molecular potency, diffusion (passive), and spread (active); (g) Differing reconstitution volumes; and (h) Increased number of injection sites can affect spread, onset, and duration of effect. Conclusions: The principles of BoNT‐A use in aesthetics are complex yet understandable as outlined in the framework of the updated Eight Key Clinical Postulates and serves as a useful tool for providing the most effective treatment and interpreting research on present and future toxin formulations.