Botulinum toxin A versus B in sialorrhea: A prospective, randomized, double-blind, crossover pilot study in patients with amyotrophic lateral sclerosis or Parkinson's disease.

Background: Either botulinum toxins (BoNTs) A and B have been used for improving drooling in different neurological conditions. Methods: Consecutive patients affected by Amyotrophic Lateral Sclerosis (ALS) or Parkinson's Disease (PD) accompanied by severe drooling were randomized to receive botulinum neurotoxin type A (BoNT-A) or B (BoNT-B) injections into the salivary glands. Following the first treatment, when sialorrhea returned to baseline (at least three months after the first injection), subjects were re-treated with the other serotype. Ultrasound-guided injections into parotid and submandibular glands were bilaterally performed: total doses were 250 U BoNT-A (Dysport) and 2500 U BoNT-B (Neurobloc). Objective (cotton roll weight) and subjective (ad hoc clinical scales) evaluations were performed at baseline, after 1 and 4 weeks, and every 4 weeks until drooling returned to baseline. Results: Twenty-seven patients (15 ALS and 12 PD) were enrolled, fourteen completed the study. BoNT-A and BoNT-B treatments gave both subjective and objective improvements in all patients. The latency was significantly shorter after BoNT-B treatments (3.2 ± 3.7 days) compared to BoNT-A (6.6 ± 4.1 days; P = 0.002). The mean benefit duration was similar at 75 and 90 days for BoNT-A and BoNT-B, respectively (P = NS). The only toxin-related side effect was a change to saliva thickness. Conclusions: Either 250 U Dysport or 2500 U Neurobloc have similar effectiveness and safety in controlling sialorrhea. BoNT-B has a shorter latency and comparable duration. Cost analysis, considering the doses used in this study protocol favored BoNT-B treatment.