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Key Takeaways
  • Dry mouth is a common side effect of CPAP therapy, resulting from mouth breathing, decreased saliva production, and mask leaks.
  • Address dry mouth with heated tubing, a humidifier, chin straps, and mask adjustments.
  • Talk to your doctor about adjusting your CPAP pressure settings if dry mouth continues.

Continuous positive airway pressure (CPAP) helps many people breathe better while they sleep, but using a CPAP machine can take some getting used to. Among other challenges, CPAP users often wake up with a dry mouth. Fortunately, there are some adjustments that can make CPAP more comfortable to use.

CPAP is one of the main treatments for obstructive sleep apnea, a common and serious sleep disorder. Obstructive sleep apnea causes a sleeping person’s airway to close during sleep, leading to repeated breathing problems throughout the night. A CPAP machine prevents these closures by continuously pumping air into the airway.

Although it has benefits, CPAP can also cause dry mouth and other side effects, especially on first use. Preventing dry mouth can make using CPAP a better experience and can encourage people to continue this important therapy.

How CPAP Machines Can Cause Dry Mouth

CPAP users may experience dry mouth for several reasons.

  • Mouth breathing: Some people using CPAP may exhale through the mouth rather than the nose. Exhaling through the mouth during sleep can dry it out.
  • Poorly fitting mask: A CPAP mask that is too loose or too tight can contribute to dry mouth, as well as reduce the treatment’s effectiveness .
  • Decreased flow of saliva: Research suggests that the high pressure in the mouth created by CPAP can block the flow of saliva , which normally keeps the mouth moist.

Other Causes of Dry Mouth

Using a CPAP machine is not the only cause of dry mouth while sleeping. Obstructive sleep apnea itself, even when a person is not using CPAP, can increase the risk of dry mouth. Several other factors may also contribute to this symptom.

  • Medications: Dry mouth is a common side effect of antihistamines, decongestants, and many other medications.
  • Dehydration: Dehydration occurs when there is not enough fluid in the body. It may be caused by not taking in enough fluid or by losing fluid through diarrhea, vomiting, or excessive urination or sweating.
  • Advanced age: The sense of thirst can diminish as people age, which may lead them to drink less and become dehydrated.
  • Salivary gland problems: Salivary glands produce the saliva that moistens the mouth. The salivary glands’ normal function can be disrupted by infections, cancer treatment, and diseases such as Sjögren’s syndrome.
  • Additional possible causes: Diabetes, anxiety, HIV infection , and the use of tobacco, marijuana , and methamphetamine can all contribute to mouth dryness.

How to Stop CPAP Dry Mouth

CPAP users can take a number of steps to alleviate dry mouth. The best solution depends on the main cause of the problem.

Keep the CPAP Airflow Moist

One step that may reduce dry mouth is moistening the airflow through the CPAP by using a humidifier. Humidification can also help if the nose gets dried out , which often accompanies dry mouth .

Different methods may be used for humidification. The choice of method can depend on personal preference and the type of CPAP machine.

  • Inline heat moisture exchange humidifiers: These devices warm the air circulating from the CPAP machine and add moisture to it.
  • Built-in humidifiers: Many CPAP machines include built-in humidifiers with adjustable temperature settings.
  • Cold passover humidifiers: This style of humidifier moistens air as it passes over room temperature water without heating it.
  • Heated tubing: Some CPAP machines use heated tubing to increase the moisture level and temperature of the pumped air, which may help with dry mouth.
  • Room humidifiers: If dry air in the environment is contributing to dry mouth, a standalone humidifier can help moisten the air in the bedroom and provide relief.

Keep the Mouth Closed

A frequent cause of dry mouth for CPAP users is mouth breathing, in which the mouth is open during sleep. Keeping the mouth closed with a chin strap or adhesive strips can reduce mouth breathing and relieve dry mouth.

  • Chin strap: Chin straps encircle the head and gently cradle the chin to keep it closed. Research shows that chin straps increase people’s willingness to continue using CPAP .
  • Adhesive strips: CPAP users may also use disposable adhesive strips applied over the mouth to encourage sleeping with the mouth closed.

Relieve Nasal Congestion

Nasal congestion can lead to mouth breathing, especially in children with obstructive sleep apnea. Relieving nasal congestion with saltwater nasal sprays or medication may help control mouth breathing.

Find the Best CPAP Mask

A CPAP mask that fits poorly or seals improperly can cause air leaks and dry mouth. Selecting a face mask is part of the initial set-up when people begin using CPAP. But it is common for people to switch to another mask if problems arise once they start using CPAP at home. A doctor or sleep specialist can provide guidance on the most appropriate options.

Many styles and sizes of CPAP masks are available, and some can address specific concerns. For example, a mask that covers both the nose and mouth may improve mouth dryness, particularly if chin straps are not effective.

Additional Tips for Using a CPAP Machine

Don’t be discouraged if it takes some time to get used to using CPAP. While you adjust, you can take steps to make your CPAP machine less burdensome to use.

  • Prevent skin irritation: Ensuring that the mask is clean can help prevent skin problems. Skin creams or pads may also prevent skin irritation.
  • Eliminate noise: If the noise of the CPAP machine is bothersome, try putting it under the bed so it doesn’t sound as loud.
  • Take advantage of innovations: As CPAP technology improves, new devices and approaches to making CPAP more comfortable may become available. If you have a problem with your CPAP, mention it to your health care provider. There may be a new product that can benefit you.

When to Talk to Your Doctor About CPAP Dry Mouth

If side effects like dry mouth are preventing you from using your CPAP as directed, you may be missing out on the many health benefits regular CPAP use can deliver. If mouth dryness is a problem, tell your doctor. Mention any other side effects you are experiencing and anything you have tried to alleviate them. Your health care team can help you troubleshoot side effects and keep you motivated to use it.

Medical Disclaimer: The content on this page should not be taken as medical advice or used as a recommendation for any specific treatment or medication. Always consult your doctor before taking a new medication or changing your current treatment.

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12 Sources

  1. Brown, L. K. & Lee, W. (2021, September 17). Titration of positive airway pressure therapy for adults with obstructive sleep apnea. In N. Collop (Ed.). UpToDate.

  2. Rowland, S., Aiyappan, V., Hennessy, C., Catcheside, P., Chai-Coezter, C. L., McEvoy, R. D., & Antic, N. A. (2018). Comparing the efficacy, mask leak, patient adherence, and patient preference of three different CPAP interfaces to treat moderate-severe obstructive sleep apnea. Journal of Clinical Sleep Medicine, 14(1), 101–108.

  3. Bortolotti, M. (2017). The cause of dry mouth during CPAP application. Journal of Clinical Sleep Medicine, 13(4), 647.

  4. Chang, V. T. (2022, February 28). Approach to symptom assessment in palliative care. In T. J. Smith (Ed.). UpToDate.

  5. Hennessy, B. J. (2022, February). Dry mouth (Xerostomia). Merck Manual Consumer Version.

  6. Wang S. W. (2022, April 21). Cannabis (marijuana): Acute intoxication. In M. M. Burns & S. J. Traub (Eds.). UpToDate.

  7. Rinaldi, V., Costantino, A., Luchena, A., & Casale, M. (2022, March 2). Sleep-disordered breathing and CPAP treatment and management. Medscape.

  8. Ghadiri, M., & Grunstein, R. R. (2020). Clinical side effects of continuous positive airway pressure in patients with obstructive sleep apnoea. Respirology, 25(6), 593–602.

  9. Knowles, S. R., O’Brien, D. T., Zhang, S., Devara, A., & Rowley, J. A. (2014). Effect of addition of chin strap on PAP compliance, nightly duration of use, and other factors. Journal of Clinical Sleep Medicine, 10(4), 377–383.

  10. Halbower, A. C. (2020, November 4). Continuous positive airway pressure (CPAP) for pediatric obstructive sleep apnea. In: R. D. Chervin (Ed.). UpToDate.

  11. Genta, P. R., Kaminska, M., Edwards, B. A., Ebben, M. R., Krieger, A. C., Tamisier, R., Ye, L., Weaver, T. E., Vanderveken, O. M., Lorenzi-Filho, G., DeYoung, P., Hevener, W., & Strollo, P. (2020). The importance of mask selection on continuous positive airway pressure outcomes for obstructive sleep apnea. An official American Thoracic Society workshop report. Annals of the American Thoracic Society, 17(10), 1177–1185.

  12. Strohl, K. P. (2021, July 8). Patient education: Sleep apnea in adults (Beyond the basics). In N. Collop (Ed.). UpToDate.


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