Original ArticlesAcute Treatment of Trigeminal Neuralgia With Onabotulinum Toxin AZúñiga, Carlos MD*; Piedimonte, Fabian MD†; Díaz, Sergio MD*; Micheli, Federico MD, PhD*Author Information *Parkinson’s Disease and Movement Disorders Program, Hospital de Clínicas José de San Martín, School of Medicine, University of Buenos Aires; †CENIT Foundation for Neuroscience Research and School of Medicine, University of Buenos Aires. Conflicts of Interest and Source of Funding: Dr Federico Micheli has received honoraria for consultancy and conferences from Allergan, Ipsen, Merz, Biotoscana, Schering Plough, Glaxo and Novartis. The remaining authors have no conflicts of interest to declare. Address correspondence and reprint requests to Federico Micheli, MD, PhD, Juncal 1695 Piso 5 J Zip Code 1062 C.A.B.A., Argentina; E-mail: email@example.com Clinical Neuropharmacology: September/October 2013 - Volume 36 - Issue 5 - p 146-150 doi: 10.1097/WNF.0b013e31829cb60e Buy Metrics Abstract A double-blind, randomized, placebo-controlled study of patients with essential trigeminal neuralgia and treatment with a single injection of onabotulinum toxin A (BTX) was carried out. The efficacy, safety, and tolerability of either 1 mL 0.9% saline plus 50 U of BTX or only 1 mL of 0.9% saline injected subcutaneously in the affected area were evaluated. Cases with involvement of the third branch of the trigeminal nerve also received intramuscularly either 10 U of BTX or matching placebo in the masseter muscle, ipsilateral to the pain location. Pain was assessed with the visual analog scale (VAS). Twenty subjects were administered BTX, and 16 subjects received placebo. Two months after the intervention, a trend to statistical significance was observed for the VAS mean values in subjects treated with BTX and those who received placebo (VAS 4.9 vs 6.63, t test, P = 0.07). Three months after the injection, significant differences were observed in the average VAS score for subjects treated with BTX and those treated with placebo (VAS 4.75 vs 6.94, respectively; t test, P = 0.01). Onabotulinum toxin A was well tolerated and seems to be a safe and useful therapy for patients with essential trigeminal neuralgia. © 2013 by Lippincott Williams & Wilkins.