A double-blind placebo-controlled trial of botulinum toxin B for sialorrhea in Parkinson's disease

Background: Injections of botulinum toxin A are an effective treatment for sialorrhea in Parkinson's disease (PD). Based on the relatively high rates of dry mouth seen with botulinum toxin B, there is reason to suspect that it may also improve sialorrhea. Objective: To determine whether botulinum toxin B (Myobloc; Elan Pharmaceuticals, New York, NY) is a safe and effective treatment for sialorrhea in patients with PD. Methods: Demographics, PD treatments, head posture, the Unified Parkinson's Disease Rating Scale (UPDRS), two questionnaires regarding drooling, Visual Analogue Scale, global impressions, salivary gland imaging, and a dysphagia questionnaire were assessed in 16 PD subjects with problematic sialorrhea. Patients were then randomized to receive either botulinum toxin B (1,000 units into each parotid gland and 250 units into each submandibular gland) or a pH-matched placebo, using only anatomic landmarks. Patients returned 1 month later to undergo an identical assessment. Results: Compared with placebo, those randomized to drug reported improvement on the Visual Analogue Scale (p<0.001), global impressions of change (p<0.005), Drooling Rating Scale (p<0.05), and Drooling Severity and Frequency Scale (p<0.001). There was no change in UPDRS, head posture, or Dysphagia Scale. Adverse events were mild and included dry mouth (three patients), worsened gait (two), diarrhea (one), and neck pain (one) in the botulinum toxin B group. Conclusion: Anatomically guided injections of botulinum toxin B into the parotid and submandibular glands appear to effectively improve sialorrhea without compromising dysphagia in patients with PD.