When prescription drugs and saliva don’t mix

Some of the most commonly prescribed drugs in the U.S. — think any of the classes with the prefix “anti” — can have an unintended side effect. Here, Texas A&M College of Dentistry faculty and residents break down this cause of dry mouth and how they help patients cope.

For many Americans, prescription drug use has become the norm, not the exception. According to the most recent statistics available from the Centers for Disease Control and Prevention, 48.7 percent of Americans used at least one prescription drug in the preceding month. Individuals taking three or more prescription drugs rounded out at more than 21 percent, followed by more than 10 percent of the population taking five or more prescription medications.

While not a surprise to dentists and dental hygienists, learning that some of the most prescribed drugs in the U.S. are known to cause xerostomia, or dry mouth, paints an unsettling connection. Perhaps you’ve heard of some: There’s antihypertensive (blood pressure) meds Norvasc and Zestril, antilipemic (cholesterol) brand names Zocor and Lipitor, anti-anxiety medication Xanax, antidepressants Zoloft and Celexa and even anti-ulcer agent Prilosec. These household names are just a few of the 348 medications that can cause dry mouth, according to an Oct. 2012 issue of the Gordon J. Christensen “Clinicians Report.”

Jane Cotter, assistant professor in the Caruth School of Dental Hygiene at the College of Dentistry, explains the dilemma: “If it’s not a medication that’s designed to increase the removal of fluid from the body, like a diuretic, it’s something that’s affecting the parasympathetic nervous system.

“The body doesn’t know the difference, so if we’re going to suppress one thing, then all of the functions of that system will be suppressed. The problem that we see is that many patients are on several of these medications. It’s the combination that really shows the effects.”

Taking these medications doesn’t mean an immediate sentence to dry mouth, and diagnosing the condition isn’t done merely by taking a patient’s word for it. First, a check into the medical history can help reveal, at a glance, any disease processes requiring medication. An assessment of the patient’s oral mucosal tissues and salivary flow comes next, starting with an attempt to stimulate the salivary glands located in the cheek and under the tongue. It’s something dental hygiene students check for during every intraoral and extraoral exam.

If the mirror sticks to the mouth, if the saliva is frothy and doesn’t pool, if the tongue looks fissured — even shiny — suspicions are confirmed.

“The tongue isn’t shiny because it’s wet; it’s shiny because it’s dry,” Cotter says.

It’s not solely use of prescription medications that can cause dry mouth, Cotter adds. Side effects from cancer treatment radiation or health conditions such as Sjögren’s syndrome are just a couple other culprits.

“It’s always been an issue,” Cotter says of medications and dry mouth. “Now that the baby boomers are getting older, it’s more prominent, more widespread.”

Resident Dr. John D. Corey ’16 sees patients with dry mouth on a daily basis in the Advanced Education in General Dentistry program at the college. He estimates a third of his patients fit into this category, and of those, many are on the severe end of the xerostomia spectrum.

“The majority of the patients I see with dry mouth symptoms are taking multiple medications,” Corey says. “From my own personal experience, I have noticed a correlation between the number of ‘anti’ medications a patient is taking and the severity of their dry mouth symptoms.”

When Corey notices signs of dry mouth during an exam, questions follow.

“I ask them if they ever have trouble chewing, swallowing or speaking,” Corey says. “The conversation that ensues allows me to assess the impact of their dry mouth on their overall quality of life.”

It’s something that most of us simply take for granted. Without proper salivary flow, eating everyday staples such as bread can become a difficult endeavor. And sans the protective coating of saliva, crunchy foods like potato chips can stick to and cut the inside of the mouth.

“They don’t have enough saliva to soften food and swallow it,” Cotter explains. “If the xerostomia is severe, they can have trouble eating and swallowing.”

Faculty and students throughout the school take a closer look at medication upon the first sign of dryness in patients seen at the clinic. In some situations, Cotter will consult with the patient’s physician, which may result in a change of medication; in other cases, a mere switch in the drug brand can make a difference. With more severe situations, medications that stimulate salivary flow may be added to the patient’s current regimen. It’s an option that works with patients on “anti” prescriptions but not cancer patients whose cells have been damaged from radiation.

Other options include saliva stimulators — think gums and lozenges. Saliva substitutes with a glycerol base help coat the mouth, and rinses with calcium phosphate and sodium bicarbonate — some of the compounds that mimic the natural electrolytes found in saliva — help moisten and comfort the tissue. The only problem: the staying power of such rinses is limited to 20 minutes.

Patients in this moderate to severe dry mouth category are put on a more frequent recall schedule, Cotter explains, since xerostomia correlates with an increased risk of decay, periodontal disease and fungal infections.

“As hygienists, we want to educate the patient on the effects of dry mouth, encourage good oral hygiene and give some suggestions on things to comfort the dry oral tissue,” Cotter says.