Higher dosage of botulinum toxin type A for glabellar lines - implications for efficacy and safety
Higher dosage of botulinum toxin type A for glabellar lines - implications for efficacy and safety
Injection of botulinum toxin (Botox®) is generally a very safe and well-tolerated method of smoothing wrinkles. The treatment effect usually sets in after 48–72 hours, and the maximum effect is reached after 1–2 weeks. In rare cases, it may take longer for the effect to set in. The duration of effect is typically between 4 and 6 months. It is not uncommon for patients to ask for a higher dose in order to possibly prolong the duration of effect, but without this being at the expense of safety. In a systematic review, Kaufman-Janette et al. (Toxins (Basel). 2021 Jul; 13(7): 494.) explored precisely this question.
The meta-analysis:
For their meta-analysis, the authors drew on a total of 5 randomised, double-blind, high-dose studies (published from 2015 onwards) on the treatment of glabellar lines with botulinum toxin type A. Preparations approved in the USA or Europe were considered (AbobotulinumtoxinA, IncobotulinumtoxinA and OnabotulinumtoxinA). A “high dose” was defined as an administered dose higher than that approved according to the prescribing information (10 Speywood units/injection point for AbobotulinumtoxinA, 4 Allergan units and Merz units for OnabotulinumtoxinA and IncobotulinumtoxinA, respectively).
The results:
The present review suggests that a higher (off-label) dose of botulinum toxin type A can increase the duration of effect without compromising the safety profile of the preparations. With a 2- to 2.5-fold increase in the on-label dose of AbobotulinumtoxinA or a 5-fold increase in the on-label dose of IncobotulinumtoxinA, a median duration of effect of approx. 9 months has been documented. With a 2- to 4-fold increase in the on-label dose of OnabotulinumtoxinA, a median duration of effect of approx. 6 months has been documented.
Conclusion:
It remains important that patient satisfaction and naturalness are not impaired (e.g. by a so-called “frozen look”) at a higher dose. In addition, the focus should be on relevant anatomical structures. Although further studies and data are needed for a definitive conclusion, this systematic review shows that a higher (off-label) dose of botulinum toxin type A can lead to more effective and individually tailored results.
Source:
Kaufman-Janette et al. Toxins (Basel). 2021 Jul; 13(7): 494.