Background     Xerostomia (dry mouth) is a common symptom at the end of life – affecting more than 75% of hospice patients – and is a cause of significant morbidity and diminished quality of life.  This Fast Fact will review the causes and treatments of xerostomia.

Salivary Functions include hydration, lubrication, and antimicrobial defense of the oral mucosa.  Decreased salivation can lead to oral pain; accelerated dental morbidity; oral infections, fissures, and ulcerations; halitosis; alteration in taste and enjoyment of food; chewing and swallowing difficulties; nutritional impairment; trouble producing intelligible speech; and denture-related problems.   Xerostomia is usually—although not always—associated with diminished salivary secretion (hyposialia). 

Etiologies 

• Medications with anticholinergic activity are the most common pharmacologic causes of xerostomia; these include many antiemetics, antihistamines, antipsychotics, antispasmodics, antidepressants (especially the tricyclics), and bronchodilators.  Sympatholytics are also common culprits, including alpha-blockers (e.g. terazosin), alpha-2 agonists (e.g. clonidine), and beta-blockers (e.g. metoprolol).  Medication-induced xerostomia may also result from direct interference with or damage to salivary tissue (as with some cancer chemotherapies).  Opioids and benzodiazepines cause dry mouth, although the mechanisms are not known. 
• Radiation for head and neck malignancies.
• Medical comorbidities such as HIV/AIDS, diabetes, renal failure, and Sjögren’s syndrome.
• Psychiatric comorbidities such as mood and anxiety disorders.
• Dehydration from any cause including drug-induced.

Treatment

• Address underlying causes.  Eliminate unnecessary drugs or substitute less drying ones.  If this is not feasible, titrate to lowest effective dose or modify dosing schedule.  Replacing immediate-release with controlled-release formulations of some drugs may help (e.g. with oxybutynin and tolterodine for overactive bladder). 
• Stimulate residual gland function. 
  • Sugarless gums and candies can stimulate salivary reflexes.  Products sweetened with xylitol are anticariogenic; those containing vitamin C may reduce salivary viscosity.
  • Cholinergic agonists such as pilocarpine and cevimeline. Therapeutic effect is rapid for drug-related xerostomia; latency is greater (often 8-12 weeks) for xerostomia related to radiotherapy. Pilocarpine is started at 5 mg po tid and can be titrated to 10 mg po tid. Cevimeline is dosed at 30 mg po tid. Urinary frequency, dizziness, and sweating are common side effects and may be attenuated with intake of dairy products. These agents are contraindicated in asthma, acute iritis, and narrow-angle glaucoma, and should be used with caution in COPD and cardiac disease. 

• Saliva substitutes.  Most have limited efficacy; many patients find frequent sips of water more useful and convenient.  Topical products containing olive oil, betaine, and xylitol have been found effective for medication-induced xerostomia (e.g. Xerostom® products). Newer products with enzyme systems such as lactoperoxidase, lysozyme, and glucose oxidase (e.g. Biotène® Oralbalance Dry Mouth Gel)—offer potential antimicrobial and moisturizing benefits.  Due to limited duration of action, they may be particularly useful before eating, speaking, and sleeping.   Recently, custom oral appliances with artificial saliva reservoirs have become available and may be particularly useful at night.
• Encourage oral hydration.  Humidifiers, especially during sleep, may also be helpful.
• Optimize oral hygiene. 
• Antimicrobial mouthwashes (alcohol-free).  Chlorhexidine gluconate oral rinse, USP 0.12%, twice daily, may be effective in preventing dental caries and oral infections.
• Most toothpaste products contain the surfactant sodium lauryl sulfate (SLS), which can irritate dry mucosa and inactivate the enzyme systems of the newer artificial salivas.  Biotène® Dry Mouth Toothpaste contains salivary enzymes and is SLS-free. 

References

1. Amerongen AVN, Veernan ECI. Current therapies for xerostomia and salivary gland hypofunction associated with cancer therapies. Support Care Cancer. 2003; 11:226-231.
2. Chambers MS, Rosenthal DI, Weber RS. Radiation-induced xerostomia. Head & Neck. 2007; 29:58-63.
3. Frost PM, Shirlaw PJ, Challacombe SJ, et al. Impact of wearing an intra-oral lubricating device on oral health in dry mouth patients. Oral Diseases. 2006; 12:57-62.
4. Jensen SB, Pederson AM, Reibel J, Nauntofte B. Xerostomia and hypofunction of the salivary glands in cancer therapy. Support Care Cancer. 2003; 11:207-225.
5. Miller M, Kearney N. Oral care for patients with cancer: a review of the literature. Cancer Nurs. 2001; 24:241-254.
6. Scully C. Drug effects on salivary glands: dry mouth. Oral Diseases. 2003; 9:165-176.
7. Shiboski CH, Hodgson TA, Ship JA, Schiodt M. Management of salivary hypofunction during and after radiotherapy. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2007; 103(suppl 1):S66.e1-S66.e.19.
8. Ship JA, McCutcheon JA, Spivakovsky S, Kerr AR. Safety and effectiveness of topical dry mouth products containing olive oil, betaine, and xylitol in reducing xerostomia for polypharmacy-induced dry mouth. J Oral Rehabil. 2007; 34(10):724-734.

Version History:  Originally published June 2007.  Revised, and 2nd edition published, December 2008.  Version re-copy-edited in May 2009; then again July 2015.