September/October 2009

Medications and Oral Health
By Annie Lam, PharmD, CGP, FASCP
Aging Well
Vol. 2 No. 4 P. 22

Margaret tried several different medications for her urinary incontinence. The problem was so acute that she avoided going out in public. Recently, her physician prescribed a new drug that has almost completely stopped the incontinence. She feels more confident and is relaxed enough to go out to lunch with friends. However, at her last dental visit, her dentist was shocked to find multiple new areas of tooth decay. After noting that her mouth was very dry, he asked her about any changes in medications. He was concerned about her use of a drug to treat incontinence that is known to have significant drying effects on the mouth, which can cause tooth decay. But she is reluctant to give up the medication that has effectively controlled her incontinence.

What happened to Margaret is not unusual. Many older adults find that a medication that works for one chronic disease has adverse side effects in another area.

Maintaining oral health is crucial for the overall well-being of older adults because gum disease, tooth decay, and the pain associated with these conditions can impair an individual’s ability to eat, speak, and socialize and can adversely affect an elder’s quality of life. Many frail older adults are at high risk for poor oral health due to a decline in their ability to independently maintain their daily oral hygiene. Some medications, including prescription medications, over-the-counter products, and herbal preparations, can adversely affect oral health. It is important for older adults to be aware of the potential oral health risks of medications since many are using multiple medications for chronic health conditions. Additionally, elders should communicate with their physicians, pharmacists, and dentists to identify potential strategies to prevent and/or manage the potentially harmful side effects of their medications.

Troublesome Oral Conditions
The most common medication-induced oral condition is xerostomia, or dry mouth. Other common problems include oral mucosal lesions, gum problems such as gingival hyperplasia, change in taste, and infections.

Xerostomia
Dry mouth is a side effect common to many medications. More than 400 medicines reportedly cause dry mouth by reducing the secretion of saliva. Drying of the oral tissues and reduced buffering capacity caused by insufficient saliva secretion can affect the normal oral flora, increase susceptibility to irritation and infection, affect chewing and swallowing, and increase the vulnerability of root and tooth caries and gum problems. For elders wearing dentures, decreased salivary flow can also lead to severe denture retention problems due to decreased mucous secretion and drying of gum tissue that supports dentures.

Medications that can cause dry mouth are those with anticholinergic side effects, such as anti-Parkinson’s drugs, antidepressants, antipsychotics, sedative hypnotics, antihistamines, and antianxiety medications. Tricyclic antidepressants and the selective serotonin reuptake inhibitors used to treat depression are well known to cause dry mouth. Patients using either the older antipsychotic agents, such as haloperidol and thorazine, or the newer antipsychotic medications, such as risperidone, olanzapine, and quetiapine, have reported problems with dry mouth. Xerostomia is also a known adverse effect of antianxiety and sedative hypnotic medications such as lorazepam, oxazepam, temazepam, zolpidem, and triazolam. Some medications that are prescribed to treat urinary incontinence (oxybutynin and tolterodine), as well as many common over-the-counter antihistamines, decongestants, antinausea agents, and iron supplements, also have been associated with dry mouth.

While medication-induced xerostomia is common among older adults, this condition is often reversible, as medications affect only salivary secretion and do not actually damage salivary glands. Discontinuing the use of such medications and switching to products with less potential to cause dry mouth is an effective strategy to address this problem.
Among cancer patients receiving radiation therapy, especially those suffering from head and neck cancer, radiation-induced xerostomia is a common complication because radiation to this region can destroy salivary glands. The damage is often irreversible, and the extent of damage of radiation-induced xerostomia is related to the dose, area, and duration of exposure.

Mucosal Problems
The two most common oral mucosal problems are lichenoid lesions (white striations) and erythema multiforme (red lesions), both of which can be painful at times. These conditions are known to be associated with the use of antibiotics such as clindamycin, anticonvulsants such as carbamazepine and phenytoin, a medication to treat diabetes (chlorpropamide), and ibuprofen. These conditions often disappear after the offending medications are discontinued.

Gum Problems
Some medications can lead to swelling of gum tissue, also known as gingival hyperplasia. Antiepilepsy medications such as phenytoin, sodium valproic acid, topiramate, and lamotrigine have been implicated in this condition. Calcium channel blockers, such as amlodipine, verapamil, and diltiazem, which are commonly used to treat hypertension and angina, and cyclosporin A, an immunosuppressant, have also been reported to cause gingival hyperplasia.

Taste Disturbance
Some older adults are susceptible to taste decline and/or taste disturbance, which can increase the risk of loss of appetite, malnutrition, and weight loss. Medications can cause a total loss of the ability to taste (ageusia), decreased sensitivity to taste (hypogeusia), or a distortion in taste (dysgeusia). Often these conditions are self-limiting and reversible with the discontinuation of the offending drug.

Angiotensin-converting enzyme inhibitors commonly used to treat hypertension have been reported to cause reversible distortion of taste. Medications used to treat fungal infections in nails, namely griseofulvin and terbinafine, when taken by mouth, can also lead to reversible taste disturbance. Anti-infective medications such as metronidazole and clarithromycin have been reported to cause either loss of taste or altered taste. Penicillamine, a medication used to treat Wilson’s disease, has been reported to cause dose-related loss of taste that is reversible within eight to 10 weeks without discontinuing the medication.

Fortunately, medication-induced taste disturbance is reversible in most cases, and discontinuing the use of the offending medications is the best way to address this problem.

Infections
Medications that alter normal oral bacterial flora can potentially lead to yeast overgrowth and candidiasis. Candidiasis is a common condition found in patients suffering from xerostomia because reduced salivary flow alters the acidity in the mouth and favors yeast growth. Other medications such as corticosteroids (e.g., prednisone) can suppress the immune system and increase the risk of oral infections. Corticosteroid inhalers used to control asthma can predispose the mouth to candidiasis. Antibiotics, anticancer, and immunosuppressive medications can also induce oral candidiasis.

Management of Medication-Induced Oral Conditions
Maintaining good oral hygiene, identifying offending medications, and reducing the use of medications with oral side effects are effective strategies to prevent medication-induced gum problems, infection, and/or tooth decay. Older adults should consult regularly with their medical providers or pharmacists to identify, discontinue, and/or replace the offending medications with those that have fewer oral side effects. However, in situations when these medications are needed, oral hygiene that includes regular use of antimicrobial mouthwashes and plaque removal by dental professionals at regular intervals are good strategies to prevent the potential complications of dry mouth, gum problems, and oral infections.

Shifting the intake time of some medications from bedtime to mealtime is a self-care measure to reduce potential complications of dry mouth, as salivary flow rate is lowest at bedtime. Food stimulates salivary secretion and can counteract the drying effect of some medications. However, this change in medication intake time can be done only when there are no contraindications, such as reduced absorption of the drug or interactions with food or other drugs. Increasing fluid intake by taking small sips of water throughout the day can reduce feelings of dry mouth and moisturize oral tissue. Saliva substitutes in spray, gum, liquid, and gel form are available commercially. The simple act of chewing can increase salivary secretion, and chewing sugarless gum has been reported to reduce feelings of dry mouth.

It’s important for older adults to be aware of the many potential side effects of medications on oral health. The best strategy is to raise questions about any potential adverse effects when a new medication is prescribed and to maintain good communication with the primary care provider, pharmacist, and dentist when signs of oral problems arise. What may seem like a normal change in the mouth may actually be a serious condition that can be prevented through elders’ greater awareness and involvement of elders’ healthcare teams.

— Annie Lam, PharmD, CGP, FASCP, is director of the University of Washington School of Pharmacy Residency Programs, codirector of the university’s School of Pharmacy Plein Certificate Program in Geriatric Pharmacy Practice, and a pharmacy department senior lecturer.