Adverse events associated with botulinum toxin injection: A multidepartment, retrospective study of 5310 treatments administered to 1819 patients.

Abstract Background: The injection of botulinum toxin is now commonly used for many therapeutic and cosmetic purposes but because of its increased use more adverse events are being reported. Objective: To evaluate and analyze the safety of botulinum toxin injections in terms of purpose and the type of toxin administered. Materials and Methods: Data were collected on 1819 patients who underwent a total of 5310 treatments between 2005 and 2011. A multivariable GEE with the logistic link function was used to identify the factors associated with adverse events. Results: Among the 5310 botulinum toxin treatments in our study cohort, 184 adverse events were recorded. The highest number of adverse events (8.29%) was associated with the treatment of blepharospasm and the lowest (1.07%) with masseter hyperplasia. By multivariate analysis, the odds ratio for females was 1.577 (P = 0.027) and for the dose was (P = 0.005). When compared with upper face wrinkles, the odds ratio was 2.510 (P = 0.002) for blepharospasm, 0.375 (P = 0.002) for cervical dystonia, and 0.114 (P = 0.035) for masseter hyperplasia. Conclusion: When injecting botulinum toxin for cosmetic purposes, practitioners should be cautious, especially when targeting the areas around the eyes.