Medications That Cause Dry Mouth

Last Updated on September 6, 2022 by Dr Gustavo Assatourians DDS

Dry mouth: relevance and risk predictors

Dry, chapped lips secondary to chronic xerostomia. Clinical signs in the oral cavity show a dry appearance of the tongue with evidence of fissuring.


Based on its pathogenesis, dry mouth syndrome is classified as true xerostomia (xerostomia vera, primary). It results from a malfunction of the salivary glands, or pseudo xerostomia. It is also called symptomatic xerostomia (xerostomia spuria, symptomatic), in the course of which the patient has the subjective impression of oral dryness despite the normal secretory function of the salivary glands.


Normal saliva secretion oranges from 0.25 to 0.35 mL/min, but it can increase with external stimulation, e.g., chewing paraffin blocks, to 1.0–3.0 mL/min.(1)A diagnosis of salivary gland dysfunction can  be made with imaging, including sialography, scintigraphy with technetium-99m, a computed tomography scan, or magnetic resonance imaging of the salivary glands.

Laboratory tests  will help determine if the underlying cause is related to a systemic disease. For instance, to evaluate for Sjögren syndrome, anti-Ro and anti-La antibodies can be tested. A minor salivary gland biopsy  (from the lower lip)can also be performed, particularly for cases of suspected Sjögren syndrome.. With this disease, histopathologic testing indicates at least one area of dense infiltrate of at least 50 lymphocytes/4 mm2. 

Xerostomia affects millions of people throughout the world. The results of clinical studies suggest that this problem affects mostly menopausal women due to estrogen deficiency, and individuals above 65 years of age.  It is also diagnosed in approximately 20% of 18- to 34-year-old individuals. 


The extent of injury in treated patients (such as cancer) is determined by the absorbed dose of radiation, the duration of exposure, and the size of the irradiated area. Initial signs of xerostomia, which additionally impair quality of life, are observed as early as a few days after irradiation. Initially, an reversible dysfunction of the salivary glands develops in irradiated patients after receiving a 10 Gy dose. Irreversible impairment of salivary gland function is associated with doses ranging between 50 and 60 Gy. A 60% decrease in the secretion of saliva has been observed immediately after radiotherapy (1,5).

A subjective feeling of xerostomia may occur in patients taking drugs that regulate  blood pressure, antidepressants, or immunosuppressive drugs. The latter cause a decrease in blood flow to the salivary glands, which may lead to reduced saliva production. This occurs quite often among patients with arterial hypertension, coronary thrombosis, diabetes, and thyroid diseases at the same time, requiring the use of different drugs.

Appetite-suppressing drugs may cause the sensation of dry mouth as well. An example of such a drug is sibutramine.


The autoimmune disease, Sjögren syndrome, is the most recognized autoimmune disease associated with hyposalivation, leading to dry mouth. In this condition, the salivary glands are targeted by the immune system. They become infiltrated by a combination of macrophages, mast cells, B cells, T cells, and plasma cells. The plasma cells produce antibodies anti-Ro and anti-La, which target the muscarinic 3 receptor, leading to atrophy of the glands.


Many patients develop chronic GVHD, which may involve the salivary and lacrimal glands, resulting in primary Sjögren syndrome-like manifestations that have a major adverse impact on quality of life.On the other hand, immunocompromised patients as a consequence of radiotherapy or chemotherapy are more apprehensive than the healthy ones.


Dry mouth correlates with numerous clinical and psychosocial problems. Clinical problems are common in patients with hyposalivation and include plaque and calculus accumulation, rampant caries, gingival inflammations, fungal infections, rhagades, limited denture retention, or limitations in swallowing, eating, and speaking. Moreover, xerostomia has a significant impact on the quality of life of affected patients. 

Dry mouth

Plaque and calculus accumulations in a patient with severe salivary hypofunction and xerostomia


Education of the patient is vital, aimed at the implementation of systematic and proper oral hygiene. It is a priority in the prevention and treatment of mouth dryness and is reflected in excellent therapeutic outcomes. Avoidance of dry, acidic, and salty foods is recommended, as is the elimination of stimulants, especially tobacco and alcohol.

Increasing humidity in the evening and avoiding crunchy, spicy, acidic, or hard foods may also be helpful. Medical management of any underlying diseases may improve clinical manifestations, as will lifestyle modifications. Discontinuing medications that cause dry mouth or switching  to alternative agents should be considered if it is safe and necessary for the patient. 

To alleviate the symptoms associated with dry mouth, saliva substitutes are frequently employed. Today, numerous products differing in pharmaceutical form are available on the market, including sprays, gels, mouthwashes, toothpastes, or gums. However, the efficacy of saliva substitutes is controversial. (4) Emerging preventive measures for xerostomia include administration of botulinum toxin or systemic growth factors, producing regenerative salivary gland tissue through transplantation or gene therapy, and the use of tempol, a radioprotective agent. However, further studies are required. 

Pilocarpine hydrochloride in a 2.5–10 mg dose can improve salivary flow in irradiated patients; however, its application is limited to certain cases. 

Pilocarpine is contraindicated in patients suffering from drug-induced xerostomia associated with the intake of medications for hypertension, asthma, or hyperthyroidism; in patients with narrow-angle glaucoma, angina, chronic bronchitis, nephrolithiasis or cholelithiasis; and those who have had myocardial infarctions.

Witsell et al. confirmed the efficacy of cevimeline administered in 30 mg doses three times per day in patients irradiated with > 40 Gy to the head and neck region. After six weeks of treatment, the mucosal status of these patients returned to its pre-radiotherapy level. 

Gómez-Moreno et al.  obtained satisfactory results using a combination of 1% malic acid with xylitol and fluorides to attenuate the signs of xerostomia in patients treated with antihypertensive agents. Although xylitol and fluoride ions do not modulate the secretion of saliva, they reduce the cariogenic and erosive potential of malic acid.

Other systemic sialogogues include bethanechol, anethole trithione, and yohimbine. Bethanechol is a carbamic ester of β-methylcholine resistant to cholinesterase, and it affects the M3 receptors. It is beneficial in patients with dry mouth after head and neck radiation and can increase salivary flow rate. The recommended dose is 25 mg three times daily. Side effects include diarrhea and nausea. A clinical trial of anethole trithione, a cholagogue and bile secretion-stimulating medication, produced improvement in dry mouth and increased salivary flow. Yohimbine, an α2- adrenoceptor antagonist, may be effective for xerostomia in patients taking psychotropic medications, according to one small study. 


Other reported treatments for xerostomia include acupuncture and intraoral electrostimulation. Hyperbaric oxygen for patients who have undergone radiation has been reported to increase salivary function. Patients who have undergone head and neck radiation may also find relief with amifostine, a cytoprotective agent, or intensity-modified radiation therapy.


The issue can be adequately addressed in different fields, including restorative, geriatric, prophylactic, and prosthetic dentistry. Also it can be empowering  to carry around a bottle with water and drink a small amount frequently. Dry mouth is not a major problem that all people suffer from, but when it occurs, there is a need to balance the buccal environment.

If you need help contact us at Channel Island Family Dental, as well as on our Facebook page. At Channel Island Family Dental, we are always attentive to your needs to make a timely diagnosis. In addition, our dentists in Oxnard, Santa Paula, Newbury Park  Ventura, and  Port Hueneme will guide you to the best treatment to give you back your best smile.



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