Adverse Events of Botulinum Toxin Type A in Facial Rejuvenation: A Systematic Review and Meta-Analysis.

[BACKGROUND] Botulinum toxin A (BTX-A) is a medical product that is used widely in cosmetics, and concern over the safety profile has increased among injectors and patients.

[OBJECTIVE] The purpose was to enhance the statistical effect size using a meta-analysis to detect the incidence rate of adverse events (AEs) in the treatment of facial wrinkles.

[METHODS] A systematic search was performed for randomized, double-blind, placebo-controlled trials published through July 2015.

[RESULTS] We searched 16 trials, including 42,405 individual participants, and found that in all enrolled facial rejuvenation studies, patients in the BTX-A group had significantly more AEs than those patients in the placebo group (RR = 1.24; 95 % CI 1.07-1.43; p = 0.003). For crow's feet lines injection analysis, the BTX-A group did not exhibit any significant increase in AEs compared with the control group (RR = 1.19; 95 % CI 0.96-1.48; p = 0.12), except in injection site hematoma (RR = 2.14; 95 % CI 1.13-4.07; p = 0.02) in the treatment group. For frown wrinkle injection analysis, AEs were significantly observed in the BTX-A group (RR = 1.47; 95 % CI 1.23-1.77; p < 0.0001), particularly headaches (RR = 1.53; 95 % CI 1.15-2.03; p = 0.003), eyelid ptosis (RR = 5.56; 95 % CI 1.68-18.38; p = 0.005), and heavy eyelids (RR = 6.94; 95 % CI 1.27-37.93; p = 0.03).

[CONCLUSION] This meta-analysis confirmed the safety profile of BTX-A for glabellar and crow's feet lines, and BTX-A usage for the removal of upper facial wrinkles, which have some significant mild-to-moderate adverse profiles, including headache, eye disorder, eyelid ptosis, and heavy eyelids. Facial injectors should abide by the technical standards of neurotoxic drugs and be familiar with the local pharmacological effects to lessen the severe side effects.

[LEVEL OF EVIDENCE I] This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the A5 online Instructions to Authors www.springer.com/00266 .