Global Pharmacovigilance of Aesthetic Botulinum Toxin Type A: Analysis of Adverse Event Reports From the <scp>USA</scp> , Europe, Canada, and Australia

BACKGROUND: Monitoring of adverse events for aesthetic BoNT-A (BoNT-A) through pharmacovigilance databases provides critical insight into real-world safety profiles. Previous analyses suggested substantial underreporting, yet comprehensive international multi-database analysis remains absent. METHODS: Adverse event reports for aesthetic BoNT-A indications were extracted from FDA FAERS, EMA EudraVigilance, Health Canada MedEffect, and TGA DAEN databases from 2002 to 2025. Reports were filtered for cosmetic indications using procedure codes, anatomical sites, and indication descriptions. Events were categorized by clinical manifestation and severity using MedDRA classification. RESULTS: Analysis identified 43,809 adverse event reports across four databases. FDA FAERS contributed 38,321 reports (87.5%), EudraVigilance 3,526 (8.0%), Health Canada 1,835 (4.2%), and TGA DAEN 127 (0.3%). Effectiveness issues comprised 57.3% of reports (n = 25,092), followed by local injection-site reactions (19.7%, n = 8,611), facial paresis/ptosis/asymmetry (9.9%, n = 4,348), and headache (6.0%, n = 2,650). Peak reporting occurred in 2018 for FAERS (1,375 reports) and 2020 for Health Canada (242 reports). Among FAERS reports with brand attribution, onabotulinumtoxinA accounted for 86.8%, abobotulinumtoxinA 9.7%, and incobotulinumtoxinA 2.4%. Co-reported adverse event analysis revealed drug ineffective with therapeutic response decreased as the most frequent pairing (n = 2,947), followed by drug ineffective with off-label use (n = 1,102). CONCLUSIONS: The predominance of effectiveness issues over traditional safety concerns distinguishes aesthetic BoNT-A pharmacovigilance from typical pharmaceutical surveillance. Geographic concentration of reporting in the United States despite global market distribution indicates systematic underreporting internationally. These findings suggest current pharmacovigilance systems inadequately capture aesthetic medicine adverse events, with direct implications for patient safety and regulatory oversight.