Comparing the effectiveness and adverse effects of pilocarpine and cevimeline in patients with hyposalivation

Evaluation and management of dry mouth and its complications in rheumatology practice

INTRODUCTION

The symptom of dry mouth has multiple potential etiologies and can be a diagnostic clue to the presence of common systemic diseases encountered in rheumatology practice. The presence of decreased saliva flow (i.e. salivary hypofunction) defines a subset of dry mouth patients in whom there may be reversible drug effects, an iatrogenic insult such as head and neck irradiation, or a disease that directly involves the salivary glands (e.g. Sjögren's disease). The assessment of salivary hypofunction includes sialometry, salivary gland imaging, salivary gland biopsy, and an assessment for relevant systemic diseases. Optimal management of dry mouth requires accurate definition of its cause, followed by general measures that serve to alleviate its symptoms and prevent its complications.

AREAS COVERED

Through a literature search on xerostomia and salivary hypofunction, we provide an overview of the causes of dry mouth, highlight the potential impact of salivary hypofunction on oral and systemic health, detail routine evaluation methods and treatment strategies, and emphasize the importance of collaboration with oral health care providers.

EXPERT OPINION

Our Expert Opinion is provided on unmet needs in the management of dry mouth and relevant research progress in the field.

Efficacy of bethanechol chloride in the treatment of radiation-induced xerostomia in patients with head and neck cancer: A systematic review and meta-analysis

BACKGROUND AND PORPUSE

Salivary glands sustain collateral damage following radiotherapy (RT) to treat cancers of the head and neck, leading to complications, including xerostomia and hyposalivation. This systematic review (SR) with meta-analysis was performed to determine the effectiveness of bethanechol chloride in preventing salivary gland dysfunction in this context.

MATERIALS AND METHODS

Medline/Pubmed, Embase, Scopus, LILACS via Portal Regional BVS and Web of Science were searched electronically in accordance with the Cochrane manual and reported PRISMA guidelines.

RESULTS

170 patients from three studies were included. Results from the meta-analysis suggest that bethanechol chloride is associated with increases in: whole stimulating saliva (WSS) after RT (Std. MD 0.66, 95% CI 0.28 to 1.03, P < 0.001); whole resting saliva (WRS) during RT (Std. MD 0.4, 95% CI 0.04 to 0.76, P = 0.03); and WRS after RT (Std. MD 0.45, 95% CI 0.04 to 0.86, P = 0.03).

CONCLUSION

The present study suggests that bethanechol chloride therapy may be effective in patients with xerostomia and hyposalivation.

Protective Effect of Electroacupuncture on Chemotherapy-Induced Salivary Gland Hypofunction in a Mouse Model

Radiotherapy and chemotherapy can impair salivary gland (SG) function, which causes xerostomia and exacerbate other side effects of chemotherapy and oral infection, reducing patients' quality of life. This animal study aimed to assess the efficacy of electroacupuncture (EA) as a means of preventing xerostomia induced by 5-fluorouracil (5-FU). A xerostomia mouse model was induced via four tail vein injections of 5-FU (80 mg/kg/dose). EA was performed at LI4 and LI11 for 7 days. The pilocarpine-stimulated salivary flow rate (SFR) and salivary glands weight (SGW) were recorded. Salivary immunoglobulin A (SIgA) and lysozyme were determined via enzyme-linked immunosorbent assay (ELISA). SG was collected for hematoxylin and eosin staining to measure acini number and acinar cell size. Tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and aquaporin 5 (AQP5) mRNA expressions in SG were quantified via RT-qPCR. 5-FU caused significant decreases in SFR, SGW, SIgA, lysozyme, AQP5 expression, and acini number, while TNF-α and IL-1β expressions and acinar cell size were significantly increased. EA treatment can prevent 5-FU damage to the salivary gland, while pilocarpine treatment can only elevate SFR and AQP5 expression. These findings provide significant evidence to support the use of EA as an alternative treatment for chemotherapy-induced salivary gland hypofunction and xerostomia.

Patient satisfaction and impact of salivary flow rate on effectiveness of xerostomia products

OBJECTIVES

To determine the types of products used to treat dry mouth and their perceived effectiveness, the relationship between salivary function and xerostomia symptoms, and whether salivary function predicts response to management strategies.

STUDY DESIGN

Cross-sectional study of 87 patients with dry mouth and documented unstimulated whole salivary (UWS) and stimulated whole salivary (SWS) flow rates. Participants completed a questionnaire assessing dry mouth complaints and symptoms and effectiveness of specific dry mouth products.

RESULTS

Mean (SD) age was 61.7 (12.9) years including 78 (90%) females. 47 (54%) participants had Sjögren's disease. Oral dryness symptoms (0-10 scale) rated highest with a mean (SD) of 7.2 (2.17); other symptoms scored from 3.4 to 5.1. Lower levels of UWS and SWS were associated with worse dry mouth and difficulty speaking, while lower levels of SWS flow alone were associated with greater difficulty swallowing and a decline in taste. More than half of the participants (55%, n = 48) reported using ≥4 dry mouth products. Participants with normal SWS flow had significantly better responses to lozenges and prescription products.

CONCLUSIONS

Patients with dry mouth and normal stimulated flow rates (i.e., residual salivary capacity) respond better to stimulatory products (parasympathomimetic and lozenges). Salivary flow rate assessments may help with recommendations of dry mouth products.

Efficacy of auricular acupuncture in improving dry mouth among an institutionalised older population: A randomised controlled study

AIMS

To investigate the efficacy of applying auricular acupuncture (AA) treatment in improving dry mouth in institution-dwelling older adults.

BACKGROUND

Dry mouth (xerostomia) is a common distressing problem in older populations, especially for institution-dwelling older adults that can affect oral health and quality of life.

DESIGN

A randomised controlled trial was conducted from December 2020 to March 2021 and performed according to STRICTA guidelines extended from the CONSORT statement.

METHODS

Older adults aged more than 65 years were randomly allocated to an AA group (n = 37) with an 8-week actual auricular points treatment or a control group (n = 38) receiving sham auricular point acupuncture. Measurements comprised a subjective assessment of the level of dry mouth as assessed by a visual analogue scale in a xerostomia questionnaire, and an objective assessment of the physiological wetness of the lingual mucosa measured with a moisture-checking device. A generalised estimating equation model was used for data analyses.

RESULTS

After completing an 8-week AA intervention stimulating the Shenmen, Point Zero and Salivary Gland 2-prime points, the AA group exhibited significantly improved subjective symptoms of dry mouth comprised of difficulty speaking (B = -6.47, p < .001), difficulty swallowing (B = -6.73, p < .001), the amount of oral saliva (B = -5.38, p < .001), a dry throat (B = -7.53, p < .001) and thirst (B = -8.06, p < .001) compared with the control group. Moreover, the AA group had higher objective oral saliva flow than the control group (B = 4.73, p < .001).

CONCLUSION

AA is an effective non-pharmacological method for improving subjective symptoms of dry mouth and objective saliva secretion in older populations living in nursing homes.

RELEVANT TO CLINICAL PRACTICE

Performing regular AA on the Shenmen, Point Zero and Salivary Gland 2-prime auricular points can be considered an alternative treatment approach to improve dry mouth in institution-dwelling older adults.

Salidroside Ameliorates Radiation Damage by Reducing Mitochondrial Oxidative Stress in the Submandibular Gland

Radiotherapy for patients with head and neck cancer inevitably causes radiation damage to salivary glands (SGs). Overproduction of reactive oxygen species (ROS) leads to mitochondrial damage and is critical in the pathophysiology of SG radiation damage. However, mitochondrial-targeted treatment is unavailable. Herein, both in vitro and in vivo models of radiation-damaged rat submandibular glands (SMGs) were used to investigate the potential role of salidroside in protecting irradiated SGs. Cell morphology was observed with an inverted phase-contrast microscope. Malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), mitochondrial ROS, mitochondrial membrane potential (MMP), and ATP were measured using relevant kits. The mitochondrial ultrastructure was observed under transmission electron microscopy. Cell apoptosis was determined by Western blot and TUNEL assays. Saliva was measured from Wharton’s duct. We found that salidroside protected SMG cells and tissues against radiation and improved the secretion function. Moreover, salidroside enhanced the antioxidant defense by decreasing MDA, increasing SOD, CAT, and GSH, and scavenging mitochondrial ROS. Furthermore, salidroside rescued the mitochondrial ultrastructure, preserved MMP and ATP, suppressed cytosolic cytochrome c and cleaved caspase 3 expression, and inhibited cell apoptosis. Together, these findings first identify salidroside as a mitochondrial-targeted antioxidant for preventing SG radiation damage.

Normal salivary production using a swab method in clinical settings

Objectives

The purpose of the study was to generate age‐ and gender‐based normative data for unstimulated salivary flow rate (uSFR) by means of a swab method, and to provide preliminary results of using the test in patients suspected of reduced salivary function.

Methods

The 130 healthy participants without subjective xerostomia or suspicion of reduced salivation were recruited. Measurements of uSFR were conducted three times per subject and mean uSFR was calculated for the entire population and stratified according to age and gender. The method was applied in a pilot population of 25 patients suffering from either Sjögren's syndrome or had underwent irradiation of the head and neck.

Results

Mean uSFR in the healthy group was 0.808 g/min (range: 0.165–2.442). Not significant trends towards declining uSFR with increasing age and higher uSFR in women were seen. Mean uSFR in the patients was 0.429 g/min (range: 0.111–1.448), which was significantly lower than normative values. Use of xerogenic drugs correlated to lower uSFR.

Conclusion

Age‐ and gender‐based normative data of uSFR was presented using a fast and readily implementable swab test. The test was able to objectively verify hyposalivation among patients suffering from Sjögren's syndrome or having been exposed to head and neck radiation.

A Review on the Role of Pilocarpine on the Management of Xerostomia and the Importance of the Topical Administration Systems Development

Xerostomia is linked to an increased risk of dental caries, oral fungal infections, and speaking/swallowing difficulties, factors that may significantly degrade patients’ life, socially- or emotionally-wise. Consequently, there is an increasing interest in developing management approaches for confronting this oral condition, at which pilocarpine, a parasympathomimetic agent, plays a vital role. Although the therapeutic effects of orally administrated pilocarpine on the salivary gland flow and the symptoms of xerostomia have been proved by numerous studies, the systemic administration of this drug is affiliated with various adverse effects. Some of the typical adverse effects include sweating, nausea, vomiting, diarrhea, rhinitis, dizziness and increased urinary frequency. In this vein, new strategies to develop novel and effective dosage forms for topical (i.e., in the oral cavity) pilocarpine administration, in order for the salivary flow to be enhanced with minimal systemic manifestations, have emerged. Therefore, the purpose of the current review is to survey the literature concerning the performance of topical pilocarpine delivery systems. According to the findings, the topical delivery of pilocarpine can be regarded as the equivalent to systemic delivery of the drug, efficacy-wise, but with improved patient tolerance and less adverse effects.

Neuropharmacology of Cevimeline and Muscarinic Drugs-Focus on Cognition and Neurodegeneration

At present, Alzheimer’s disease (AD) and related dementias cannot be cured. Therefore, scientists all over the world are trying to find a new approach to prolong an active life of patients with initial dementia. Both pharmacological and non-pharmacological pathways are investigated to improve the key symptom of the disease, memory loss. In this respect, influencing the neuromodulator acetylcholine via muscarinic receptors, such as cevimeline, might be one of the therapeutic alternatives. The purpose of this study is to explore the potential of cevimeline on the cognitive functions of AD patients. The methodology is based on a systematic literature review of available studies found in Web of Science, PubMed, Springer, and Scopus on the research topic. The findings indicate that cevimeline has shown an improvement in experimentally induced cognitive deficits in animal models. Furthermore, it has demonstrated to positively influence tau pathology and reduce the levels of amyloid-β (Aβ) peptide in the cerebral spinal fluid of Alzheimer’s patients. Although this drug has not been approved by the FDA for its use among AD patients and there is a lack of clinical studies confirming and extending this finding, cevimeline might represent a breakthrough in the treatment of AD.

Acute and cumulative benefits of Photobiomodulation for xerostomia: A systematic review and meta-analysis

The objective was to explore the effectiveness of photobiomodulation therapy for treating patients who suffer xerostomia and/or hyposalivation due to the most prevalent clinical diagnoses. We searched PubMed, Scopus, Web of Science, CINAHL and Cochrane Library for randomized or clinical controlled trials published until 31 October 2019. Risk of bias assessment and meta-analysis were conducted using the Cochrane tools. A total of 274 records were retrieved, and 11 met the inclusion criteria. Interventions whose parameters ranged between wavelengths of 790-830 nm (infrared), 30-120 mW of power and an energy density below 30 J/cm-2 were associated with improvements in xerostomia/hyposalivation. As for the assessment of methodological quality, 10 of the 11 articles included had a high risk of overall bias. Only 3 articles provided sufficient information to conduct a meta-analysis for quality of life, compared with placebo in patients with burning mouth syndrome, showing a standardized mean difference between groups from baseline of -0.90 (-1.48; -0.32). The present review and meta-analysis suggest that photobiomodulation therapy is an effective, non-invasive and safe approach in patients with xerostomia. However, despite the potential, it is not possible to reach a reliable consensus on the parameters to be used, and future studies should be conducted by standardizing intervention protocols.