Fibromyalgia (FM) is a chronic pain condition defined by widespread musculoskeletal pain that persists over a long period. This complex syndrome is also characterized by significant non-pain symptoms, including fatigue, stiffness, sleep disturbances, and cognitive difficulties. A frequently reported symptom associated with FM is Xerostomia, which is the medical term for the subjective sensation of having a dry mouth. This oral dryness typically results from reduced salivary flow, known as hyposalivation. Understanding this link is important for managing the full spectrum of FM symptoms.
Prevalence of Dry Mouth in Fibromyalgia
Chronic dry mouth is significantly more common among individuals with FM compared to the general population. A substantial portion of FM patients report Xerostomia symptoms, with prevalence reaching 70.9% in some studies, contrasting sharply with approximately 5.7% in control groups.
Dry mouth is a frequent co-occurring symptom, often considered part of a broader set of related conditions known as sicca symptoms. Xerostomia involves a persistent, sticky dryness that makes swallowing, speaking, and tasting foods difficult. This lack of moisture can also lead to a burning sensation in the mouth or throat, known as glossodynia, which is common among FM patients.
Dry mouth is strongly associated with the chronic pain condition but is generally viewed as a secondary effect or associated feature, rather than a primary cause of the pain itself. The high frequency suggests a shared underlying mechanism related to the body’s overall dysregulation in FM.
Factors Contributing to Xerostomia
The reasons FM patients frequently experience dry mouth are multifaceted, involving both the disorder’s biological features and the pharmacological treatments used to manage it. The most common cause of Xerostomia is often the medication prescribed to alleviate their main symptoms. Many drugs used to treat chronic pain, sleep issues, and mood disturbances—such as tricyclic antidepressants, serotonin-norepinephrine reuptake inhibitors (SNRIs), and certain muscle relaxants—possess anticholinergic properties.
These anticholinergic agents block the action of acetylcholine, a neurotransmitter responsible for stimulating various involuntary bodily functions, including salivation. By inhibiting this nerve signal, these medications reduce the production and flow of saliva from the salivary glands. Since polypharmacy, or the use of multiple medications, is common in managing FM, the combined effect of several drugs can significantly worsen the dryness sensation.
Beyond pharmacological effects, a non-medication-related mechanism is also believed to play a role, pointing toward an underlying dysregulation of the Autonomic Nervous System (ANS). The ANS controls involuntary functions like heart rate, digestion, and salivation. FM is known to involve a hyper-responsive stress system, and when the body is in a state of stress or sympathetic overdrive, it naturally suppresses saliva production, prioritizing other functions.
Research has demonstrated that a significant number of FM patients report dry mouth even when they are not taking xerogenic medications, suggesting that the disorder’s underlying nervous system dysfunction contributes directly to reduced salivary flow. While dry eyes and dry mouth (sicca symptoms) are common in FM, most patients do not meet the diagnostic criteria for Sjögren’s Syndrome, which is an autoimmune disease that directly attacks the salivary glands. This distinction confirms that dry mouth in FM is typically a symptom of nervous system or medication-related effects.
Strategies for Managing Chronic Dry Mouth
Managing chronic dry mouth is important for comfort and for preventing serious secondary oral health issues. Saliva provides a protective barrier, and its reduction significantly increases the risk of tooth decay, gum disease, and oral infections. Adopting specific lifestyle and hygiene practices is a crucial first step toward relief.
Lifestyle Adjustments
Maintaining hydration throughout the day by frequently sipping water helps keep the oral tissues moist. Patients should avoid substances that further dehydrate the mouth, such as caffeine, alcohol, and tobacco products. Using a cool-mist humidifier in the bedroom at night introduces moisture into the air, which is particularly helpful for those who breathe through their mouth while sleeping.
Over-the-Counter and Hygiene Measures
For immediate relief, over-the-counter products are available, including saliva substitutes, moisturizing sprays, and lozenges. Chewing sugar-free gum or sucking on sugar-free hard candies, especially those containing xylitol, can help stimulate the natural flow of saliva. Diligent oral hygiene is non-negotiable, requiring the use of fluoride toothpaste and frequent dental check-ups.
If dry mouth persists and significantly impacts quality of life, consultation with a healthcare provider is warranted. Doctors may adjust the dosage of current medications or explore alternative treatment options that have fewer anticholinergic side effects. Physicians may also prescribe saliva stimulants, such as pilocarpine or cevimeline, which increase the natural production of saliva from the remaining functional salivary gland tissue.