Table 3

A summary of botulinum toxin for the management of sialorrhoea

Toxin typesDue to multiple type A botulinum toxin subtypes, it is difficult to make direct comparisons between the effects of type A and type B toxins. When treating sialorrhoea, the comparative dose of botulinum toxin A (Botox) to botulinum toxin B is approximately 1:10.45
Type A
  • There are subtypes of type A botulinum toxin, two of which (Botox and Dysport) are commonly used to treat sialorrhoea. These subtypes have different biological activities; thus, dose adjustments must be made accordingly (Botox 1:3 Dysport).46

Type B (NeuroBloc)
  • Has a greater propensity for autonomic effects.46

  • Has a higher immunogenicity and so repeated use may have a greater risk of antibody-induced failure.47 48

  • Commonly used doses in trials to date: 100 MU of Botox, 250 MU of Dysport, 2500 MU of NeuroBloc.

  • Doses should be divided between the submandibular and parotid glands, with the parotid receiving a greater fraction of the total dose.

  • Optimal therapeutic dose not established. Titrate as appropriate.49

DeliveryUS guidance
  • Confirms accurate delivery of the toxin

Landmark guided
  • Practical and largely considered safe (figure 3)

Outcomes of treatment with botulinum toxinAdvantages50
  • Meta-analysis data supporting its clinical efficacy

  • Effective in patients with symptoms resistant to medications

  • Effects last for 3–6 months

  • Fewer side effects than anticholinergic medication

  • Minimally invasive

  • May decrease risk of aspiration pneumonia in neurologically impaired children.51

  • Common adverse effects: xerostomia, thickened bronchial secretions and viscous saliva, difficulty chewing and pain at the site of injection. Reverse slowly as toxin effect wears off.52

  • Dysphagia is a rare side effect.53

  • Repeat injections may result in antibody formation and fading efficacy.49

Group characteristics
  • Patients with motor neurone disease may be more prone to adverse effects and shorter benefit duration compared with those with Parkinson’s disease.

  • Old age may be associated with longer benefit duration.53

  • MU, mouse units; US, ultrasound.