Posted August 20, 2022 by Anusha ‐ 6 min read
Xerostomia, commonly known as dry mouth, is a condition in which the person’s salivary glands don't make enough saliva to keep the mouth wet. It is generally seen as a side-effect of certain medications, symptom of some medical disorders or as an adverse effect of radiation in cancer therapy. Rarely, the cause may be directly related to the salivary gland itself.
Also known as Dry Mouth, Xerotos and Waterlessness
This is the most common cause of xerostomia. Many medications that are sold over-the-counter mention dry mouth as the side-effect. Some medicines that are known to cause xerostomia are:
Medications for anxiety and depression
Drugs like anticholinergics that are used in the treatment of urinary incontinence, overactive bladder, and chronic obstructive pulmonary disorder
Decongestants and antihistamines used in allergies and cold
Some pain medicines
Some drugs are used in the treatment of high blood pressure
Certain bronchodilators used to treat asthma
Some medicines used in treatment of diarrhea
Certain muscle relaxants
Medications for Parkinson’s disease
Drugs used in chemotherapy for the treatment of cancer
Radiation treatments to the head and neck region for treatment of cancer can cause irreversible damage to the salivary glands. This can lead to a significant decrease in salivary production.
Dehydration occurs when the body loses a lot of fluids without getting replenished. This can happen during hot summer months or conditions like vomiting, diarrhea, fever, excessive sweating, blood loss, or burns. When the body is dehydrated, production of saliva is reduced leading to dry mouth.
Mouth-breathing or snoring
Breathing through the mouth due to nasal congestion or snoring while sleeping causes saliva to evaporate. This leads to dryness in the mouth.
Xerostomia can be a sign of medical conditions like:
Sjogren’s disease (formerly known as Sjogren syndrome)
Acquired immunodeficiency syndrome (AIDS)
Poorly controlled diabetes
Uncontrolled hypertension (high blood pressure)
Systemic lupus erythematosus
People might experience xerostomia as they age. The factors contributing to it can be the use of certain medications, changes in the body’s ability to process medication, inadequate or improper nutrition, or long-term health problems.
Any injury, infection, or surgery that causes damage to the nerves of the head or the neck region can result in xerostomia.
Smoking and drinking
Alcohol acts as a diuretic, meaning, as the body breaks down alcohol, it removes the water from the blood through urine. Also, smoking reduces the salivary flow rate leading to dryness of the mouth or xerostomia.
Use of recreational drugs
Meth mouth is a condition due to the use of methamphetamine that causes severe xerostomia and damage to teeth. Other drugs such as marijuana also can cause xerostomia.
Stress and anxiety
Cortisol (also called the stress hormone) is produced in excess when a person is under stress or is anxious. Increased levels of cortisol in saliva can change the composition of the saliva causing the mouth to become dry.
Medications like antidepressants and anxiolytics (anti-anxiety)
Autoimmune conditions like Sjogren’s disease and AIDS
Bulimia or anorexia
Blockage of major salivary duct such as from a salivary stone or infection
Chemotherapy and radiation to the head and neck
Patients with mental or nervous disorders
Individuals wearing dentures
Pregnancy or breastfeeding
Details about duration, frequency, and severity of dry mouth are documented. The history of dryness at other sites (eyes, nose, throat, skin & vagina) along with complete prescription drug history, health conditions, and any other symptoms along with it are obtained.
Major salivary glands are examined for the presence of any pain, firmness, or enlargement. The amount and quality of saliva coming from the ducts inside the mouth is assessed.
Examination of the mouth
There may be very little or no pooled saliva on the floor of the mouth. The saliva may appear stringy, ropy, or foamy.
The presence of dry, sticky or reddish oral mucosa is inspected.
Occasionally, fungal or yeast infections will be present, appearing as removable white plaques on the inner mucosal surface of the mouth.
Several office tests and techniques can be utilized to detect the abnormal functioning of the salivary glands.
These tests are as follows:
Also known as salivary flow measurement, it is a simple test or procedure that measures the flow rate of saliva.
In this test, collection devices are placed over the parotid gland or the submandibular/sublingual salivary gland at the opening of the duct, and saliva is stimulated with citric acid.
The normal salivary flow rate for the parotid gland when it is not stimulated is 0.4 to 1.5 mL/min/gland.
The normal flow rate for
restingthe whole saliva is 0.3 to 0.5 mL/min; for stimulated saliva, 1 to 2 mL/min.
Values less than 0.1 mL/min are generally considered xerostomic.
It is an imaging technique that may be used to detect any masses or stones in the salivary gland. It involves the injection of radio-opaque dye into the salivary glands.
It can be useful in assessing salivary gland function. Technetium-99m sodium pertechnate is injected intravenously to ascertain the rate and density of uptake and the time of excretion in the mouth.
Minor salivary gland biopsy is often used in the diagnosis of Sjögren’s syndrome (SS), HIV-salivary gland disease, sarcoidosis, amyloidosis, and graft-versus-host disease (GVHD). Biopsy of major salivary glands is an option when malignancy (cancer) is suspected.
In addition to accessing the salivary glands, some blood tests may also help in detecting any underlying infection or disease. The tests are:
Complete blood count (CBC)
Blood sugar tests
These can be used as artificial saliva that help replace the lost moisture and lubricate the mouth.
These substitutes are available commercially, but they can also be compounded.
Artificial salivas do not stimulate salivary gland production but are designed to mimic natural saliva.
Thus, they are considered as replacement therapy rather than a cure.
These salivary substitutes are available commercially as solutions, sprays, gels, and lozenges.
In general, they contain an agent to increase viscosity such as carboxymethylcellulose or hydroxyethylcellulose, minerals such as calcium and phosphate ions and fluoride, preservatives such as methylparaben or propylparaben, and flavoring and related agents.
A recently developed product called natrol dry mouth relief, which has a patented pharmaceutical grade of anhydrous crystalline maltose (ACM) is used to stimulate saliva production.
It has been used in a clinical study of patients with Sjogren’s syndrome and ACM was shown to increase secretions.
Natrol dry mouth relief is formulated as lozenges that can be dissolved in the mouth three times daily.
As its effect is to stimulate salivary glands, it is not recommended for patients whose salivary gland function has been lost through radiation therapy.
Pilocarpine: Pilocarpine is a muscarinic (M3) agonist which stimulates the secretion of saliva. It is indicated for the treatment of symptoms of xerostomia due to salivary gland hypofunction caused by Sjogren’s syndrome or by radiotherapy for cancer of the head and neck area.
Cevimeline: Cevimeline is a cholinergic agonist with a high affinity towards the muscarinic M3 receptors located on lacrimal and salivary gland epithelium, leading to an increase in the secretions of the exocrine glands. It is used to relieve the symptoms of xerostomia in patients with Sjogren’s syndrome.