Professional Reference articles are written by UK doctors and are based on research evidence, UK and European Guidelines. They are designed for health professionals to use, so you may find the language more technical than the condition leaflets.
Xerostomia (dry mouth) may be a side-effect of medication. It is also caused by irradiation of the head and neck region or by damage to or disease of the salivary glands. Patients with a persistently dry mouth may develop a burning or scalded sensation and have poor oral hygiene. They are prone to increased dental caries, periodontal disease, oral infections (particularly candidiasis) and intolerance of dentures. Where possible, treatment is directed at the underlying cause of dry mouth. If this is not possible, or is only partially successful, symptomatic treatment is used.
The diagnosis of xerostomia is usually based on a quantitative assessment of unstimulated and stimulated whole saliva. However, there is a wide variation in the amount of saliva produced by individuals and work is ongoing to devise more accurate methods of assessing salivary gland function.
Treating the underlying cause
- Drugs are a common cause of dry mouth. Reduce the dose or change the drug if possible. Morphine is a common but often overlooked cause of dry mouth. Other drugs that cause dry mouth include tricyclic antidepressants, antihistamines, antimuscarinic drugs, anti-epileptic drugs, antipsychotics, beta-blockers and diuretics.[5, 6]
- Dehydration should be treated.
- Simple measures will often relieve symptoms of dry mouth, even if rehydration is not undertaken.
- Anxiety can also cause dry mouth.
- Sjögren's syndrome - check antinuclear antibody titre.
Simple measures should be used by all patients. Dry mouth may be relieved in many patients by:
- Frequent sips of cool drinks.
- Sucking pieces of ice.
- Sucking sugar-free fruit pastilles.
- Eating partly frozen melon or pineapple chunks.
- Sugar-free chewing gum - which stimulates salivation in patients with residual salivary function.
- Petroleum jelly - which can be applied to the lips to prevent drying and cracking.
A Cochrane review found that there is no strong evidence that any topical preparation is better than simple measures for the treatment of xerostomia.Nevertheless, artificial saliva is frequently used and may help to relieve symptoms in some patients.A properly balanced artificial saliva should be of a neutral pH and contain electrolytes (including fluoride) to correspond approximately to the composition of saliva.
- Biotène Oralbalance® gel and Xerotin® oral spray are both artificial saliva preparations which have Advisory Committee on Borderline Substances (ACBS) approval for the treatment of any patient complaining of dry mouth.
- BioXtra® gel, Glandosane® aerosol spray and Saliveze® oral spray are artificial saliva preparations which have ACBS approval only for patients whose dry mouth is secondary to radiotherapy or sicca syndrome. Saliva Orthana® spray can be prescribed for any cause of dry mouth, although the lozenges remain ACBS.
These act by local stimulation of the salivary glands and are most effective in patients who have some residual salivary gland function.
- Salivix® pastilles, which act locally as salivary stimulants, are also available and have ACBS approval only for patients whose dry mouth is secondary to radiotherapy or sicca syndrome.
- SST® tablets may be prescribed for dry mouth in patients with salivary gland impairment and patent salivary ducts.
- Sugar-free chewing gum is as effective as artificial salivas.
Long-term use of acidic products may demineralise tooth enamel. Glandosane® spray, Salivix® pastilles and SST® tablets are acidic products.
- Irradiation for head and neck cancers.
- Dry mouth and dry eyes (xerophthalmia) in Sjögren's syndrome.
It can be considered for difficult cases.
- Pilocarpine is effective only in patients who have some residual salivary gland function. If there is no response it should be discontinued.
- Adverse effects include a risk of increased urethral smooth muscle tone and renal colic. Other side-effects include blurred vision and dizziness. This may affect performance of skilled tasks - eg, driving, particularly at night or in reduced lighting.
- Adequate fluid intake should be maintained to avoid dehydration associated with excessive sweating.
- Radiotherapy-induced dry mouth does not respond well to pilocarpine. One study showed that salivary gland transfer was four times more effective in this type of patient.
- Acupuncture has been found useful in the prevention of xerostomia when administered concurrently with radiotherapy.
- A technique called acupuncture-like transelectrical nerve stimulation is currently being investigated.[12, 13, 14]
Surgical transfer of one submandibular gland to the submental space facilitates shielding of the gland during postoperative radiation therapy. Studies confirm that there is no adverse effect on the function of the gland in this position.
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Further reading & references
- Multi-disciplinary Guidelines for the Oral Management of Patients following Oncology Treatment; Royal College of Surgeons of England and The British Society for Disability and Oral Health (2012)
- Matsuzaki T, Susa T, Shimizu K, et al; Function of the membrane water channel aquaporin-5 in the salivary gland. Acta Histochem Cytochem. 2012 Oct 31 45(5):251-9. doi: 10.1267/ahc.12018. Epub 2012 Sep 22.
- Jeong SY, Kim HW, Lee SW, et al; Salivary Gland Function Five Years after a Radioiodine Ablation in Patients with Differentiated Thyroid Cancer: Direct Comparison of Pre and Post-Ablation Scintigraphies and Their Relation to Xerostomia Symptoms. Thyroid. 2012 Nov 15.
- Palliative care - oral; NICE CKS, July 2015 (UK access only)
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