Xerostomia (dry mouth) may be a side-effect of other 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, intolerance of dentures, and oral infections, particularly candidiasis. 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.

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, antiepileptic drugs, antipsychotics, betablockers, and diuretics.
• 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 anti-nuclear antibody titre.

General measures

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 stimulates salivation in patients with residual salivary function.
• Petroleum jelly can be applied to the lips to prevent drying and cracking.

Available treatments

Artificial saliva

This can provide useful relief of dry mouth. A properly balanced artificial saliva should be of a neutral pH and contain electrolytes (including fluoride) to correspond approximately to the composition of saliva.

• Artificial saliva offers little advantage compared with simple measures for most patients. The few available studies are of poor quality, but suggest that many patients find no additional benefit with carmellose-based preparations compared with frequent tea, coffee, milk, or fruit juice.¹ In addition, some patients find carmellose-based products feel sticky.
• The duration of action of mucin products is only 10 to 15 minutes.
• Long-term use of acidic products may demineralise tooth enamel. Glandosane® spray, Salivix® pastilles, and SST® tablets are acidic products.
• Sugar-free chewing gum is as effective as artificial salivas.²

Consider using an artificial saliva containing mucin or lactoperoxidase when simple measures have been tried, but symptoms remain troublesome. The pH of some artificial saliva products may be inappropriate.

• Luborant® is licensed for any condition giving rise to a dry mouth.
• Biotene Oralbalance® BioXtra®, Glandosane®, Saliva Orthana®, and Saliveze®, have Advisory Committee on Borderline Substances (ACBS) approval for dry mouth associated only with radiotherapy or Sjögren's syndrome.
• Salivix® pastilles, which act locally as salivary stimulants, are also available and have similar ACBS approval.
• SST® tablets may be prescribed for dry mouth in patients with salivary gland impairment and patent salivary ducts.

Pilocarpine tablets

These are licensed for the treatment of xerostomia following:

• Irradiation for head and neck cancer
• Dry mouth and dry eyes (xerophthalmia) in Sjögren's syndrome

It can be considered for difficult cases.

• Most patients with drug-induced dry mouth usually respond to treatment after the first dose.³
• Only about 50% of patients with radiotherapy-induced dry mouth respond to treatment, and it may take up to 3 months before a response is seen.³
• Pilocarpine 5 mg three times a day is more effective than artificial saliva, but also has more adverse effects, e.g. sweating, dizziness, rhinitis, urinary frequency, and blurred vision.
• Acupuncture may be a useful alternative to pilocarpine in resistant cases.⁴
• They are effective only in patients who have some residual salivary gland function. If there is no response they should be discontinued.
• There is a risk of increased urethral smooth muscle tone and renal colic.
• Adequate fluid intake should be maintained to avoid dehydration associated with excessive sweating.
• Patients should be counselled that blurred vision or dizziness may affect performance of skilled tasks, e.g. driving, particularly at night or in reduced lighting.

Document references

1. Vissink A, s-Gravenmade EJ, Panders AK, et al; A clinical comparison between commercially available mucin- and CMC-containing saliva substitutes.; Int J Oral Surg. 1983 Aug;12(4):232-8. [abstract]
2. Davies AN; A comparison of artificial saliva and chewing gum in the management of xerostomia in patients with advanced cancer.; Palliat Med. 2000 May;14(3):197-203. [abstract]
3. Davies AN, Daniels C, Pugh R, et al; A comparison of artificial saliva and pilocarpine in the management of xerostomia in patients with advanced cancer.; Palliat Med. 1998 Mar;12(2):105-11. [abstract]
4. Johnstone PA, Peng YP, May BC, et al; Acupuncture for pilocarpine-resistant xerostomia following radiotherapy for head and neck malignancies.; Int J Radiat Oncol Biol Phys. 2001 Jun 1;50(2):353-7. [abstract]

Internet and further reading

• Dry mouth website
• Palliative care - oral problems, Clinical Knowledge Summaries (2007)
• Maltsman-Tseikhin A, Moricca P, Niv D; Burning mouth syndrome: will better understanding yield better management? Pain Pract. 2007 Jun;7(2):151-62. [abstract]

Acknowledgements