Questions :


Contributed by:

Associate Professor Dr. Ngeow Wei Cheong

Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, University of Malaya, 50603 Kuala Lumpur, Malaysia.


Dry mouth or scientifically called xerostomia, is the term used to describe the condition whereby the amount of saliva that bathes the mouth is reduced. It is rather common for the general public to experience some degree of dry mouth as a result of various underlying causes. Among the causes are radiotherapy (common in Malaysian patients suffering from head and neck carcinoma, whereby radiotherapy may be the adjunct or only mode of treatment), Sjogren's syndrome and as a complication of prolonged intake of medication. To certain extent, ageing also results in dry mouth, albeit in milder form. Assessment of the severity of dry mouth can be done in some dental hospital using Xerostomia Inventory (XI).1,2 The mean Xerostomia Inventory score in a normal population is about 17; scores above this figure indicate the degree of severity of xerostomia.

Dry mouth is a very uncomfortable condition and a common oral complaint for which patients may seek relief from the general dental practitioners. Remedies for xerostomia usually are palliative. This article reviews the different causes and options available for treating dry mouth.


Dry mouth is a frequent complication for patients who undergo radiotherapy to the head and neck region. A common group of patients seen in Malaysia are those suffering from nasopharyngeal carcinoma (NPC), which unfortunately shows a high prevalence among the Chinese due to their genetic origin. In the process of treating NPC, both parotid glands are also irradiated. The effect of radiotherapy on the salivary glands can be very rapid. It had been shown that the resting flow of parotid saliva was significantly reduced to half after only 14 hours of exposure to 2 gray (Gy) of radiation.3 A gray (Gy) is a unit used to quantify the amount of radiation one is exposed to. Besides, any residual saliva tends to be thick and viscous and so loses its ability to lubricate and cleanse.4 Dry mouth is a chronic condition in these groups of people and is irreversible especially in elderly persons. In younger people, there may be an improvement in the quality and quantity of the saliva due to stimulation of the residual salivary glands.5


Sjogren's syndrome is caused by autoimmune inflammatory exocinopathy, in another word, it is a disease where one’s body immune system attacks it's own body. Its incidence in Malaysian is unknown, but mainly affects middle-aged or elderly women.6 Its clinical features include:6

  1. dry eyes (keratoconjunctivitis sicca)
  2. Salivary and lacrimal glands swelling
  3. Dry mouth (Xerostomia)

There is no connective tissue disease in primary (as listed above), but present in secondary Sjogren's syndrome, typically rheumatoid arthritis or primary biliary cirrhosis.6

Dry mouth in Sjogren's syndrome predisposes to depapillated lobulated tongue and candidosis. The sore tongue is lobulated (not merely fissured) in quilt-like fashion and is often diffusely erythematosus as a result of candidosis.6 Diagnosis of Sjogren’s syndrome is confirmed by performing a biopsy of the minor salivary glands of the mouth. In essence, a few small salivary glands that are hidden under the lip are cut up and examined under the microscope.


It is a well-known fact that the administration of medications for various diseases has been associated with dry mouth and burning mouth syndrome. The chances of getting xerostomia increase with age and number of medications taken. Please note that in most cases, dry mouth is only noted with prolonged use of the medicine concern. Below are some of the commonly prescribed medicines that have been proven to cause xerostomia. They are listed in alphabetical order of ease of identification. The bracket on the back of the name of medicine is its purpose for prescription.

  • Albuterol (Brochodilator)
  • Alprazolam (Antianxiety)
  • Amiloride (Diuretic)
  • Amitriptyline (Antidepressant)
  • Amoxapine (Antidepressant)
  • Astemizole (Antihistamine)
  • Atropine (Antichonergic/antispasmodic)
  • Baclofen (Muscle relaxant)
  • Belladonna alkaloids (Antichonergic/antispasmodic)
  • Benztropine mesylate (AntiParkinsonian)
  • Biperiden (AntiParkinsonian)
  • Brompheniramine (Antihistamine)
  • Brompheniramine with phenylpropanolamine (Antihistamine)
  • Bupropion (Antidepressant)
  • Captopril (Antihypertensive)
  • Carbamazepine (Anticonvulsant)
  • Carbidopa with levodopa(AntiParkinsonian)
  • Carvediol (Antihypertensive)
  • Chlordiazepoxide (Antianxiety)
  • Chlordiazepoxide with clinidium (Antichonergic/antispasmodic)
  • Chlorothiazide (Diuretic)
  • Clomipramine (Antidepressant)
  • Clonidine (Antihypertensive)
  • Clorpheniramine (Antihistamine)
  • Chlorpromazine(Anti-Psychotic)
  • Chlorthalidone (Diuretic)
  • Clozapine (Anti-Psychotic)
  • Cyclizine (Antinauseant)
  • Cyclobenzaprine (Muscle relaxant)
  • Desipramine (Antidepressant)
  • Diazepam (Antianxiety)
  • Dicyclomine (Antichonergic/antispasmodic)
  • Diethylpropion (Anorexiant)
  • Difenoxin with atropine (Antidiarrheal)
  • Diflunisal (Antiinflammatory analgesic)
  • Diphenhydramine (Antihistamine)
  • Diphenoxylate with atropine (Antidiarrheal)
  • Dyphenhydramine (Antinauseant)
  • Doxepin (Antidepressant)
  • Felbamate (Anticonvulsant)
  • Fenfluramine (Anorexiant)
  • Fenoprofen (Antiinflammatory analgesic)
  • Flurazepam (sedative)
  • Fluoxetine (Antidepressant)
  • Fluvoxamine (Antidepressant)
  • Furosemide (Diuretic)
  • Gabapentin (Anticonvulsant)
  • Guanabenz (Antihypertensive)
  • Guanethidine (Antihypertensive)
  • Halazepam (Antianxiety)
  • Haloperidol (Anti-Psychotic)
  • Hydrochlorothiazide (Diuretic)
  • Hydroxyzine (Antianxiety)
  • Hyoscyamine (Antichonergic/antispasmodic)
  • Hyoscyamine with atropine, phenobarbitol & scopolamine (Antichonergic/antispasmodic)

  • Ibuprofen (Antiinflammatory analgesic)
  • Imipramine (Antidepressant)
  • Iptropium (Bronchodilator)
  • Isoproterenol (Bronchodilator)
  • Isotretinoin (Antiacne)
  • Lamotrignine (Anticonvulsant)
  • Levodopa (AntiParkinsonian)
  • Lithium (Anti-Psychotic)
  • Loperamide (Antidiarrheal)
  • Loratidine (Antihistamine)
  • Lorazepam (Antianxiety)
  • Mazindol (Anorexiant)
  • Meclizine (Antinauseant)
  • Mepoeridine (Narcotic analgesic)
  • Meprobamate (Antianxiety)
  • Methantheline (Antichonergic/antispasmodic)
  • Methscopolamine (Antichonergic/antispasmodic)
  • Morphine (Narcotic Analgesic)
  • Naproxen (Antiinflammatory analgesic)
  • Orphenadrine (Muscle relaxant)
  • Oxazepam (Antianxiety)
  • Oxybutynin (Antichonergic/antispasmodic)
  • Oxyphencyclimine (Antichonergic/antispasmodic
  • )
  • Phendimetrazine (Anorexiant)
  • Phentermine (Anorexiant)
  • Phenylpropanolamine with chlorpheniramine (Decongestant)
  • Pimozide (Anti-Psychotic)
  • Piroxicam (Antiinflammatory analgesic)
  • Prazepam (Antianxiety)
  • Prazosin (Antihypertensive)
  • Prochlorperazine (Anti-Psychotic)
  • Promazine (Anti-Psychotic)
  • Prometazine (Antihistamine)
  • Propantheline (Antichonergic/antispasmodic)
  • Pseudoephedrine (Decongestant)
  • Reserpine (Antihypertensive)
  • Scopolamine (Antichonergic/antispasmodic)
  • Temazepam (sedative)
  • Terfenadine (Antihistamine)
  • Thioridazine (Anti-Psychotic)
  • Thiothixene (Anti-Psychotic)
  • Triamterene and hydrochlorothiazide (Diuretic)
  • Triazolam (sedative)
  • Trifluoperazine (Anti-Psychotic)
  • Trihexyphenidyl (AntiParkinsonian)
  • Tripelennamine (Antihistamine)
  • Triprolidine with pseudoephedrine (Antihistamine)

Please remember that the list may be longer, so please consult your medical practitioner in case of doubt.


The treatment for dry mouth is essentially palliative, irregardless of the origin. The only one exception is for drug-induced dry mouth, whereby it may be treated by changing to different formulations where possible and practical. Consultation with the general medical practitioners is often required. The only good news for patients is that drug-induced is mild when compared to those caused by radiotherapy. Dry mouth of connective tissue disorder e.g. Sjogren's syndrome is not very common in Malaysia.

When residual secretory capacity is present, either in the major or minor salivary glands, it is advisable to stimulate the salivary glands by mechanical or gustatory stimuli regularly. For mechanical stimulation, glandular massage can be applied.

Sugarless chewing gum can be useful in providing gustatory stimulation.7 Xylitol chewing gum is advocated because of its ability to reduce Streptococcus mutans counts in plaque and saliva, and at the same time helps in remineralisation of early caries lesions.8 One such product available in the market now is the sugarless chewing gum by Biotene® and Wrigley's ®.

Alternatively, salivary flow can be stimulated by the use of cholinergic pharmaceutical preparations, such as pilocarpine or cevimeline.9 These drugs will need a medical prescription. Please consult your medical practitioner for advice.

Patients can also be given palliative oral care in the form of saliva substitutes and special mouthwashes for dry mouth e.g. Biotene®. Different types of saliva substitutes are now commercially available, containing different polymers as thickening agents, e.g. carboxymethylcellulose, polyacrylic acid, and xanthan gum.9 Study in Western population has found that mucin-based preparations may be better accepted to carboxymethylcellulose formulations10. Some patients, especially Malaysian patients find frequent sips of cold water or ice chips to be equally effective.11 Salivary substitutes or mouthwashes are useful to keep the mucosa moist, mobile and free from debris. In addition, nocturnal oral dryness can be alleviated by spraying the oral surfaces with water, or by applying a small amount of children’s dentifrice on the dental smooth surfaces. However, water is a poor lubricant. Please consult your dentist or pharmacist regarding these products.


Dry mouth is common problem seen in the general dental practice. Where there is residual salivary glands that are still functioning, stimulation could be done via massaging, use of sugarless chewing gums and prescription of systemic sialogogues. Alternatively, saliva substitute and specially formulated mouth rinse may be given to provide symptomatic relief.

*Disclaimer: The list of drugs causing dry mouth provided here are based on informations available from the manufacturers. Readers are advised to consult your medical doctor to verify this possible association.


  1. Thomson WM, Chalmers JM, Spencer AJ, Williams SM. The Xerostomia Inventory: a multi-item approach to measuring dry mouth. Community Dent Health 1998; 16: 12-7.
  2. Thomson WM, Williams SM. Further testing of the xerostomia inventory. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2000;89;46-50.
  3. Shannon IL, Trodahl JN, Starcke EN. Radiosensitivity of the human parotid gland. Proc Soc Exp Biol Med 1978; 157: 50.
  4. Joyston-Bechal S. Management of oral complications following radiotherapy. Dent Update 1992; 19: 232-4, 236-8.
  5. Carl W. Oral and dental care of patients receiving radiation therapy for tumours in and around the oral cavity. In: Carl W, Sako K eds. Cancer and the oral cavity. Chicago, Illinois: Quintessence Publishing Company, 1986; 167-83.
  6. Scully C, Cawson RA. Colour Guide Oral Medicine. Edinburgh: Churchill Livingstone, 1988.
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  8. Toors FA. Chewing gum and dental health. Literature review. Rev Belge Med Dent 1992; 47(3): 67-92.
  9. Nieuw Amerongen AV, Veerman EC. Current therapies for xerostomia and salivary gland hypofunction associated with cancer therapies. Support Care Cancer 2003; 11: 226-31.
  10. Duxbury AJ, Thakker NS, Wastell DG. A double-blind cross-over trial of a mucin-containing artificial saliva. Br Dent J 1989; 166: 115-20.
  11. McClure D, Barker G, Barker B, Feil P. Oral management of the cancer patient, part II: Oral complications of radiation therapy. Compendium 1987; 8(2):88: 90-2.


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