However, polypharmacy is thought to be the major cause in this group, with no significant decreases in salivary flow rate being likely to occur through aging alone. Drug induced
Aside from physiologic causes of xerostomia, iatrogenic effects of medications are the most common cause. A medication which is known to cause xerostomia may be termed xerogenic. Over 400 medications are associated with xerostomia. Although drug induced xerostomia is commonly reversible, the conditions for which these medications are prescribed are frequently chronic. The likelihood of xerostomia increases in relation to the total number of medications taken, whether the individual medications are xerogenic or not. The sensation of dryness usually starts shortly after starting the offending medication or after increasing the dose. Anticholinergic, sympathomimetic, or diuretic drugs are usually responsible. Sjögrens syndrome
Xerostomia may be caused by autoimmune conditions which damage saliva-producing cells. Sjögrens syndrome is one such disease, and it is associated with symptoms including fatigue, myalgia and arthralgia. The disease is characterised by inflammatory changes in the moisture-producing glands throughout the body, leading to reduced secretions from glands that produce saliva, tears and other secretions throughout the body. Primary Sjögrens syndrome is the combination of dry eyes and xerostomia. Secondary Sjögrens syndrome is identical to primary form but with the addition of a combination of other connective tissue disorders such as systemic lupus erythematosus or rheumatoid arthritis. Celiac disease
Xerostomia may be the only symptom of celiac disease, especially in adults, who often have no obvious digestive symptoms.
However, pilocarpine is not always successful in improving xerostomia symptoms. The review also concluded that there was little evidence to support the use of other parasympathomimetics in this group. Another systematic review showed, that there is some low-quality evidence to suggest that amifostine prevents the feeling of dry mouth or reduce the risk of moderate to severe xerostomia in people receiving radiotherapy to the head and neck (with or without chemotherapy) in the short- (end of radiotherapy) to medium-term (three months postradiotherapy). But, it is less clear whether or not this effect is sustained to 12 months postradiotherapy.A 2013 review looking at non-pharmacological interventions reported a lack of evidence to support the effects of electrostimulation devices, or acupuncture, on symptoms of dry mouth. Epidemiology
Xerostomia is a very common symptom. A conservative estimate of prevalence is about 20% in the general population, with increased prevalences in females (up to 30%) and the elderly (up to 50%). Estimates of the prevalence of persistent dry mouth vary between 10 and 50%. History
Xerostomia has been used as a test to detect lies, which relied on emotional inhibition of salivary secretions to indicate possible incrimination. See also
Xerosis (dry skin)

References
External links

University of Illinois at Chicago
NIH
MedlinePlus Encyclopedia
Drymouth Drymouth Drug Database