Does Metformin Cause Dry Mouth? Separating Fact From Hearsay

Metformin is one of the most widely prescribed medications for managing type 2 diabetes, but there is conflicting evidence about whether it causes dry mouth (xerostomia) or not. Understanding the cause of dry mouth is important for choosing the most effective treatment; therefore, it’s important to understand if metformin is the cause, or if something else is behind it.

 

This article examines the available evidence regarding metformin dry mouth, and explores practical ways for people with diabetes to manage dry mouth symptoms.

 

Understanding Dry Mouth and Its Consequences

Dry mouth is more than feeling dry or thirsty; it’s a medical condition that occurs when the salivary glands don’t produce sufficient saliva, or when they produce low-quality saliva. Dry mouth has several causes; the most common is medication. Hundreds of medications list dry mouth as a side effect. Other causes include radiation therapy for cancer in the head and neck regions, disease, polypharmacy, and more. 

 

A lack of saliva may not sound like a big deal, but anyone who has experienced it knows just how much of a toll it takes.

 

Saliva seamlessly enables daily activities like chewing, swallowing, and talking; it does so silently and without a lot of fanfare, so that most people don’t even realize saliva’s important role (until it’s gone). When the salivary glands malfunction, resulting in a lack of saliva, daily tasks that most people take for granted become difficult hurdles. 

 

The physical challenges caused by dry mouth often give way to emotional and social challenges. Eating and talking, two primarily social activities, become sources of frustration and embarrassment, causing stress, anxiety, and isolation. Sleep disruptions caused by dry mouth at night further contribute to emotional and physical distress, as a lack of high-quality sleep can have many harmful effects. 

 

Dry Mouth and Its Relationship to Diabetes

Dry mouth is fairly common among people with diabetes; research has found higher prevalences of xerostomia in people with diabetes (between 12.5% to 53.5%) compared to people without diabetes (0 to 30%). 

 

There are several reasons for the connection between diabetes and dry mouth:

• Polyuria, excessive urine production, is common in people with diabetes. Whereas healthy people produce between one to two liters of urine a day, people with polyuria produce more than three liters a day. Excessive urination can lead to dehydration, i.e. a lack of water in the body. As water is the basis for saliva production, chronic dehydration can lead to dry mouth. 
• Autonomic neuropathy, nerve damage from chronic high blood sugar, happens when the nerves that control the salivary glands are damaged. Thai results in dry mouth. 
• Medications and polypharmacy are common in people with diabetes; diuretics and antihypertensives manage high blood pressure, GLP-1 agonists like Ozempic and Wegovy regulate appetite and blood sugar, SGLT2 inhibitors and biguanides control blood sugar, and more. Many of these medications cause dry mouth as a side effect, and when several medications are taken at once (polypharmacy), the risk of dry mouth increases. 

 

Metformin: Medication for Blood Sugar Management

Metformin belongs to the biguanide class of drugs and is the most commonly prescribed drug to treat type 2 diabetes. It works by decreasing glucose production in the liver, increasing the body’s insulin sensitivity, and reducing intestinal glucose absorption. 

 

Common side effects include nausea, diarrhea, and bloating, although extended-release versions can minimize gastrointestinal side effects. B12 deficiency is a common long-term side effect. Missing from the list of side effects? Xerostomia.

 

So why is it then that anecdotal reports describe metformin dry mouth? 

 

What’s most likely happening in these cases is that patients who take metformin are experiencing dry mouth, but it’s likely related to a different diabetes issue, such as one of the three listed above. 

 

Dry Mouth Treatments

Understanding the source of dry mouth is important to determine which treatment is best. Since clinical research shows that metformin does not cause dry mouth, patients do not need to stop taking it. Rather, they should look for other causes, i.e. different medications, polypharmacy, polyuria, neuropathy, etc., and seek to address those issues.

 

For example, if another medication is causing dry mouth, they can try a different brand or dose; sometimes, a small change does the trick. If polypharmacy is the culprit (i.e. the patient knows they’re taking many medications at once), they can try changing doses or brands, but that can get complicated. In this case, seeking direct dry mouth symptom relief is likely the best option. 

 

Managing Dry Mouth While Taking Metformin

The best dry mouth treatment often involves a multidisciplinary approach; rather than focusing on only one area, combining several approaches is often the most effective. 

 

Medications like pilocarpine and cevimeline have proven effective in treating dry mouth. The downside of these medications is twofold:

• They have unpleasant side effects
• For people already taking several medications, adding another to the mix can increase the risk of dry mouth (the very condition they are trying to treat)

 

SaliPen is a dry mouth treatment option that works by stimulating the salivary glands to produce more saliva via painless electrical impulses to the mouth. It is FDA-approved, has no side effects, and can be used together with most dry mouth treatments. 

 

Lifestyle adjustments to lower the severity of dry mouth include:

• Drinking sufficient water
• Diabetes management: The better diabetes is managed, the less severe related symptoms will be
• Oral hygiene: Dry mouth and diabetes take a heavy toll on oral health; therefore, practicing good oral hygiene can minimize their impact
• Nighttime adjustments: Sleeping with a humidifier in the room can help reduce dry mouth at night, which tends to flare up due to the body’s natural circadian rhythm. Additionally, practicing breathing through the nose (as opposed to the mouth) can minimize oral dryness
• Artificial saliva provides temporary moisture and relief; it comes in the form of oral sprays, gels, lozenges, mouthwashes, and more
• SaliVance is a handheld oral health device that enhances oral moisture.

 

Whenever you want to incorporate a new treatment or even lifestyle adjustment, it’s important to talk to your doctor first. Diabetes is a complex disease that affects many parts of the body, so it’s important to make sure that your medical team is looped in to achieve effective, safe results. 

 

There Are Dry Mouth Solutions

While many people with diabetes experience dry mouth, you don’t need to resign yourself to discomfort and poor oral health. The many dry mouth treatments available can address dry mouth at its source and relieve symptoms. Chewing, swallowing, talking, and even sleeping don’t need to feel like monumental struggles. If you have diabetes and take metformin, talk to your doctor about dry mouth relief options. Together you can reclaim control over daily activities and enhance your quality of life.

FAQs

Is dry mouth a common side effect of metformin?

Dry mouth isn’t an official side effect of metformin, though some people who take it report xerostomia symptoms. What’s most likely happening in these cases is that there is xerostomia, but it’s caused by a different diabetes-related issue.

 

Should I stop metformin if I have dry mouth?

No! You should never make any changes to your medication without consulting your doctor. 

 

Can improving diabetes management reduce dry mouth symptoms?

Yes, dry mouth in people with diabetes is often directly related to how the disease affects the body. If diabetes management is improved, symptoms can be reduced, along with dry mouth. 

 

Are lifestyle adjustments on their own enough to treat dry mouth?

For clinical dry mouth, lifestyle adjustments are not enough to achieve relief, but they can reduce the severity of symptoms when implemented along with a clinical treatment such as SaliPen or medication.

 

How does SaliPen treat dry mouth?

SaliPen delivers mild electrical impulses to stimulate the salivary glands, promoting natural saliva flow. It’s a small handheld device that can be used at home or on the go. While it’s safe for most people, you should always consult a doctor before using any new medical device.