The following are some potential causes of dry mouth at night.

Natural variation in saliva production

According to an article in the journal Compendium, a person’s salivary glands typically produce less saliva at night. As a result, some people may notice that their mouths feel drier in the evening.

Treatment:

A doctor may prescribe special mouthwashes that can moisten the mouth and reduce sensations of dry mouth before bedtime.

People should also consider keeping a glass of water by their bedside. If a person wakes up with a dry mouth, drinking some water will help moisten the mouth.

Dehydration

According to the Oral Cancer Foundation, an estimated 20% of older adults struggle with dry mouth. In older adults, this condition usually occurs as a result of dehydration or as a side effect of certain medications.

Older adults who wear dentures may find that they no longer fit properly as a result of dry mouth. Without adequate saliva, dentures can rub against the gums, causing sore spots.

Treatment:

A person who experiences dry mouth should visit their doctor or dentist who will help determine the cause of the condition.

If dry mouth is due to the medications a person is taking, the doctor or dentist may recommend changing the dosage or switching to a different drug.

In some cases, people may receive medications to improve the function of the salivary glands.

Medication side effects

The U.S. Department of Health and Human Services state that more than 400 medicines can reduce the body’s ability to produce saliva. People who take their medications at nighttime may notice their dry mouth symptoms worsening at night.

Some medications that can cause dry mouth include:

Treatment:

A person should see their doctor if they suspect that their medication is causing dry mouth. However, people should not stop taking their medications unless they have their doctor’s approval to do so.

A doctor may suggest lowering the dosage of the medication or taking the drug earlier in the day. Sometimes, a doctor may suggest changing to a different medicine that does not cause dry mouth.

The doctor may also recommend the following:

  • taking medications with plenty of water
  • sipping on water at nighttime
  • chewing on gum to encourage saliva production
  • using a humidifier to release moisture into the air and alleviate sensations of dry mouth

Mouth breathing

Some people wake up during the night and notice that they have an extremely dry mouth. This can be a sign that they have been breathing through their mouth while asleep. Some possible causes of this behavior include:

Treatment:

The treatment for nighttime mouth breathing depends on the underlying cause. We outline the potential causes and their associated treatment options below.

Infections

Antibiotics can help to treat a bacterial infection, while decongestants may help to alleviate any associated sinus congestion.

Allergies

Antihistamines can help to treat allergies, while corticosteroids may also help to relieve any associated nasal inflammation and stuffiness.

Sleep apnea

People who experience sleep apnea may require a continuous positive airway pressure (CPAP) device. The CPAP is a mask that fits over the mouth or nose and blows air into the airways to keep them open during sleep.

Although the treatment is effective against sleep apnea, the constant stream of air can actually worsen symptoms of a dry mouth. A person should talk to their doctor or dentist who can adjust the mask or recommend a machine that does not dry out the mouth.

Narrowed nasal passages

In some cases, people who have severe difficulty breathing through their nose may require surgery to widen the nasal passages. This will help to promote airflow through the nasal passages, preventing the need for mouth breathing.

Sjogren’s syndrome

Sjogren’s syndrome is an autoimmune disorder in which the body attacks its tear glands and saliva-producing glands. As a result, a person who has Sjogren’s syndrome will typically experience sensations of dry mouth. This symptom may worsen at nighttime when the salivary glands naturally produce less saliva.

People with Sjogren’s syndrome may experience the following symptoms as a result of dry mouth:

  • difficulty swallowing food without a drink
  • pain in the mouth
  • speech problems at night

They may also experience dryness in their eyes, nose, throat, or vagina.

Treatment:

Doctors may prescribe medications to reduce dry mouth and encourage saliva production. Examples include pilocarpine (Salagen) and cevimeline (Evoxac).

A doctor will also encourage people with Sjogren’s syndrome to drink water frequently, and chew sugar-free gum to stimulate saliva production.