Xerostomia (Dry Mouth)

Why saliva matters

Saliva is produced by three pairs of major salivary glands and hundreds of minor glands, about 0.5 to 1.5 liters a day. It:

• moistens and cleans the mouth
• neutralizes acids and helps repair tooth enamel
• controls bacteria and fungi
• helps you taste, chew and swallow
• protects the lining of the mouth

Xerostomia is the symptom (feeling dry). Hyposalivation is measurably reduced saliva. They usually go together, but not always.

Causes

Medicines

More than 500 medicines can cause dry mouth. Common ones:

• antidepressants (tricyclics, SSRIs, SNRIs)
• antihistamines and decongestants
• blood pressure medicines (diuretics, beta-blockers, clonidine)
• bladder medicines (oxybutynin, tolterodine)
• antipsychotics and anti-anxiety medicines
• opioids and muscle relaxants
• Parkinson's medicines
• some inhalers

Taking several medicines increases the effect.

Medical conditions

• Sjogren's syndrome: an autoimmune disease attacking tear and saliva glands, causing dry mouth and dry eyes
• diabetes: high blood sugar causes dehydration and thirst
• dehydration from illness, vomiting, diarrhea or heat
• HIV, hepatitis C, sarcoidosis and graft-versus-host disease
• Alzheimer's disease and stroke
• anxiety
• salivary gland stones and infections

Cancer treatment

• radiation therapy to the head and neck can permanently damage salivary glands
• chemotherapy may cause temporary dryness
• radioactive iodine for thyroid disease

Lifestyle factors

• mouth breathing and snoring, especially at night
• smoking, vaping and chewing tobacco
• alcohol and caffeine
• cannabis

Symptoms

• dry, sticky feeling in the mouth
• thick, stringy saliva
• needing to sip water often, especially when eating or talking
• difficulty chewing, swallowing or speaking
• altered taste
• burning or sore mouth and tongue
• cracked lips and sore corners of the mouth
• bad breath
• problems wearing dentures
• waking at night with a very dry mouth

Complications

• tooth decay, often at the gum line and around fillings, which can progress quickly
• gum disease
• oral thrush
• mouth sores and denture sores
• poor nutrition from difficulty eating
• salivary gland infections

Diagnosis

A dentist or doctor will review your medicines and medical history and examine your mouth. Tests may include:

• measuring saliva flow
• blood tests for diabetes, Sjogren's syndrome (anti-Ro/SSA and anti-La/SSB antibodies) and other conditions
• salivary gland ultrasound or imaging
• a lip biopsy of minor salivary glands for Sjogren's syndrome

Treatment and relief

Treat the cause

• review medicines with your doctor, who may lower doses, switch drugs or change timing
• control blood sugar in diabetes
• treat mouth breathing, for example a blocked nose or sleep apnea

Relieve dryness

• sip water throughout the day and with meals
• chew sugar-free gum or suck sugar-free lozenges, especially those containing xylitol, to stimulate saliva
• saliva substitutes (sprays, gels, rinses), especially at night
• use a humidifier in the bedroom
• avoid alcohol-containing mouthwashes, alcohol, caffeine, tobacco and very salty or spicy foods
• lip balm for dry lips

Protect your teeth

• brush twice a day with fluoride toothpaste, and consider high-fluoride toothpaste or fluoride varnish from your dentist
• clean between teeth daily
• limit sugary snacks and drinks
• see your dentist every 3 to 6 months

Prescription medicines

• pilocarpine or cevimeline, which stimulate saliva production in people with some working gland tissue, such as Sjogren's syndrome or after radiation. Side effects include sweating and flushing

Frequently asked questions

What is xerostomia?

Xerostomia is the medical name for dry mouth, a persistent feeling of not having enough saliva. It is very common, especially in older adults, and usually results from medicines, medical conditions or cancer treatment rather than aging itself.

What causes dry mouth?

The most common cause is medicines, including antidepressants, antihistamines, blood pressure drugs, bladder medicines and opioids. Other causes include Sjogren's syndrome, diabetes, dehydration, radiation therapy to the head and neck, mouth breathing, smoking and cannabis.

Why is my mouth dry at night?

Saliva production naturally falls during sleep. Mouth breathing, snoring, a blocked nose, sleep apnea, dry bedroom air and medicines taken at bedtime make night-time dryness worse. A humidifier, saliva gel at bedtime and treating nasal blockage can help.

How can I relieve dry mouth?

Sip water often, chew sugar-free gum or lozenges with xylitol, use saliva substitutes, run a humidifier at night, and avoid alcohol, caffeine, tobacco and alcohol-based mouthwashes. Ask your doctor whether any of your medicines could be changed.

Can dry mouth damage your teeth?

Yes. Saliva protects teeth by neutralizing acid and helping repair enamel. A dry mouth can lead to rapid tooth decay, gum disease and thrush. Fluoride toothpaste, regular dental visits and limiting sugar help protect your teeth.