What treatments are available for managing hypersalivation in a patient with Parkinson's disease (PD)?

From the Guidelines

For a Parkinson's patient experiencing excessive salivation, botulinum toxin (BT) therapy to the salivary glands is suggested, especially for those with an inadequate response or intolerance to anticholinergic therapy, as per the latest guidelines from 2023 1. When considering treatment options, it's crucial to weigh the benefits and risks, particularly in the context of Morbidity, Mortality, and Quality of Life.

• The use of botulinum toxin injections into the salivary glands has been conditionally recommended for patients with neuromuscular disorders, including Parkinson's disease, who suffer from sialorrhea 1.
• It's essential to note that the decision between botulinum toxin therapy and radiation therapy should be based on local expertise, as the evidence does not clearly indicate which should be considered first 1.
• While anticholinergic medications are often used as first-line treatment, the provided evidence suggests considering botulinum toxin for patients who do not respond adequately to these medications or experience intolerable side effects.
• The specific dosage of botulinum toxin can vary, and clinicians should refer to individual studies for guidance on dosing 1.
• Non-pharmacological approaches, such as speech therapy to improve swallowing frequency and using sugar-free hard candies to stimulate swallowing, can also be beneficial in managing excessive salivation in Parkinson's patients.
• It's critical to monitor patients closely for potential side effects, especially when using anticholinergic medications, which can include dry mouth, constipation, urinary retention, and confusion, particularly in elderly patients.

From the FDA Drug Label

GLYCOPYRROLATE ORAL SOLUTION 1MG/5ML is an anticholinergic indicated to reduce chronic severe drooling in patients aged 3-16 years with neurologic conditions associated with problem drooling (e.g., cerebral palsy) Glycopyrrolate is a competitive inhibitor of acetylcholine receptors that are located on certain peripheral tissues, including salivary glands. Glycopyrrolate indirectly reduces the rate of salivation by preventing the stimulation of these receptors.

Glycopyrrolate oral solution may be used to help with excessive salivation in a Parkinson’s patient, as it is indicated to reduce chronic severe drooling in patients with neurologic conditions associated with problem drooling. However, the FDA label does not specifically mention Parkinson's disease as an indication.

• The recommended dose is 0.02 mg/kg three times daily, titrated in increments of 0.02 mg/kg every 5-7 days, based on therapeutic response and adverse reactions.
• The maximum recommended dose is 0.1 mg/kg three times daily, not to exceed 1.5-3 mg per dose based upon weight.
• Glycopyrrolate oral solution should be dosed at least one hour before or two hours after meals. 2

From the Research

Treatment Options for Excessive Salivation in Parkinson's Patients

• Injections of botulinum toxins in the huge salivary glands and in cricopharingeal muscle are considered the most effective methods for treating hypersalivation in Parkinson's disease 3.
• There is evidence to suggest that complaints of hypersialorrhea in Parkinson's patients are not caused by a salivary defect, but could be explained by difficulties in swallowing, which may be related to autonomic dysfunction in PD 4.

Understanding Salivary Problems in Parkinson's Disease

• Patients with Parkinson's disease have a lower salivary flow rate and higher prevalence of both xerostomia and drooling than controls 5.
• The prevalence of self-reported xerostomia in Parkinson's patients ranges from 49% to 77%, and that of self-reported drooling ranges from 5% to 80% 5.
• A multidisciplinary approach is necessary to address the complexity of salivary problems present in patients with Parkinson's disease 5.

Muscarinic Receptor Binding Changes in Parkinson's Disease

• There is evidence of selective increase in M3 receptors in cortical and subcortical regions, as well as increased M2/M4 in cortical area BA9, which together support a role for cholinergic dysfunction in PD 6.
• Muscarinic acetylcholine receptor subtypes, particularly M(1), M(4), and M(5) receptors, may be potential drug targets for the treatment of Parkinson's disease 7.