Either botulinum toxins (BoNTs) A and B have been used for improving drooling in different neurological conditions.
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.
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.
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.