A Double-Blind Randomized Controlled Trial Investigating the Most Efficacious Dose of Botulinum Toxin-A for Sialorrhea Treatment in Asian Adults with Neurological Diseases

This study aims to determine the most efficacious dose of Botulinum neurotoxin type A (BoNT-A) in reducing sialorrhea in Asian adults with neurological diseases. A prospective, double-blind randomized controlled trial was conducted over 24 weeks. Thirty patients with significant sialorrhea were randomly assigned to receive a BoNT-A (Dysport(®)) injection into the submandibular and the parotid glands bilaterally via an ultrasound guidance. The total dose given per patient was either BoNT-A injection of (i) 50 U; (ii) 100 U; or (iii) 200 U. The primary outcome was the amount of saliva reduction, measured by the differential weight (wet versus dry) of intraoral dental gauze at baseline and at 2, 6, 12, and 24 weeks after injection. The secondary outcome was the subjective report of drooling using the Drooling Frequency and Severity Scale (DFS). Saliva reduction was observed in response to all BoNT-A doses in 17 patients who completed the assessments. Although no statistically significant difference among the doses was found, the measured reduction was greater in groups that received higher doses (100 U and 200 U). The group receiving 200 U of Dysport(®) showed the greatest reduction of saliva until 24 weeks and reported the most significant improvement in the DFS score.