What Causes Mouth and Throat Dryness at Night During Sleep?

Drinking Water at Night May Be a Sign of a Sleep Disorder

Mouth dryness may occur due to many causes, including mouth breathing due to nasal congestion, medications, snoring, and sleep apnea
Mouth dryness may occur due to many causes, including mouth breathing due to nasal congestion, medications, snoring, and sleep apnea. Jonathan Knowles/Stone/Getty Images

Before wandering off to bed, you stop in the kitchen or bathroom to fill a glass of water that you set on your nightstand. Just like nearly every night, you know you’ll wake up with a dry mouth and want a few sips from it later. What causes mouth and throat dryness to occur at night during sleep? Can drinking water at night actually be a sign of a sleep disorder like snoring or sleep apnea? Learn how that glass of water might signify other problems with your breathing in sleep.

Why You Might Drink Water at Night

First, you shouldn’t need to drink water at night. In normal circumstances, our bodies provide us with the ability to go 8 hours or longer without interrupting sleep for drinking or eating. What are some of the reasons that you might need to drink water at night?

Most people drink water at night simply because their mouth becomes dry. This is sometimes called xerostomia. Feeling parched might be relatively minor or even extreme, resulting in a tongue or throat that feels as dry as a bone. There are a number of conditions that may contribute to a dry mouth.

Causes of Mouth Dryness at Night

One of the more common causes of drinking water at night may be the use of medications that cause dryness. These can include diuretics, medications that may be prescribed to treat blood pressure, swelling in the feet (peripheral edema), or heart failure. Lasix, or furosemide, is an example of a diuretic medication.

Furthermore, anticholinergic medications can also lead to dryness, such as antidepressants like amitriptyline or nortriptyline or sleeping pills that contain diphenhydramine. There are numerous medications that can contribute, and you may want to review your medication list with your pharmacist or doctor to identify any potential culprits.

If the symptom started with the use or increased dose of a medication, this makes it a more likely cause.

There are also medical conditions that might cause mouth dryness. These include diabetes, lupus, Sjogren’s, and sicca syndrome. Typically there are other symptoms as well with these disorders that would bring the diagnosis to light.

Many people experience dry mouth at night simply because they are breathing through their mouth when they sleep. This is more likely occur secondary to obstruction of the nose. This can occur with colds, allergies, or even because of structural problems such as a deviated nasal septum or enlarged turbinates. By default, we are meant to breathe through our mouths. This reduces evaporation of moisture from the soft tissues that line our airways. However, when we default to mouth breathing, the movement of the air quickly dries us out.

Mouth breathing at night is often associated with snoring. It may also occur in the context of more disturbed breathing in sleep, in the condition called sleep apnea.

These conditions may be worsened when sleeping on your back or with alcohol use near bedtime. Therefore, needing to drink water at night may be an early sign that you are not breathing well. You may be at higher risk of having these other sleep disorders affecting your breathing at night. If you use continuous positive airway pressure (CPAP) to treat sleep apnea, air escaping with mouth breathing may worsen the dryness.

How to Treat Dry Mouth at Night

If you frequently experience dry mouth at night, you may want to speak with your doctor about your concerns. As above, it will be important to rule out any medications as a cause of your problem. If there is no evidence for another medical disorder, it may be reasonable to investigate your breathing during sleep with a sleep study.

To help your mouth dryness, it may be important to start elsewhere by ensuring proper airflow through your nose. This may involve allergy treatment or even surgery to address other structural abnormalities. If you are found to have sleep apnea, treatment with CPAP may help. In rare cases, mouth moisteners such as Biotene may be recommended.

You don’t have to keep a glass of water on your nightstand. If you have mouth dryness at night, seek evaluation and get back to breathing — and sleeping — better.


Kryger, MH et al. "Principles and Practice of Sleep Medicine." Elsevier, 5th edition.

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