Oral side effects of common medications

Every time you start taking a new medicine, whether it's by prescription or over the counter, check the medication side effects. You may be surprised to learn how many drugs can cause problems in your mouth.

"Medications can affect the mouth because saliva, taste buds, and gum tissue respond very quickly to chemical changes in the body," says Jigar Mehta, a pharmacist at Harvard-affiliated Beth Israel Deaconess Medical Center.

Drugs used to treat high blood pressure, allergies, depression, anxiety, diabetes, cancer, asthma, and other conditions can cause oral side effects. Dry mouth is the most common. Others are discussed here, but this is not a complete list. That's why it's important to check the label (on over-the-counter drugs) or the patient information (for prescription drugs). Knowing what to look for can help protect your teeth, gums, and mouth. Remember, though, that just because a medication can cause side effects doesn't mean it will.

Dry mouth

More than 500 prescription and over-the-counter drugs can reduce the flow of saliva, causing dry mouth. Saliva protects the teeth and tissues in your mouth. It also helps neutralize acids and wash away bacteria that can contribute to cavities and gum disease.

People who have dry mouth can have more frequent cavities and difficulty wearing dentures. They often develop bad breath. "Dry mouth can affect quality of life, making it difficult to eat, speak, and sleep," says Mehta.

 It's estimated that around 20% of adults experience dry mouth, and the rate rises substantially in older adults, especially those on multiple medications, in some studies reaching over 70%.

Commonly used types of medications with dry mouth as a drug side effect include

• antihistamines, such as diphenhydramine (Benadryl)
• bladder medications, such as oxybutynin (Oxytrol) and solifenacin (Vesicare)
• antidepressants, including sertraline (Zoloft), fluoxetine (Prozac), venlafaxine (Effexor), and amitriptyline
• anxiety medications, such as lorazepam (Ativan)
• blood pressure medications, such as clonidine, and those in the class known as beta blockers, such as metoprolol (Lopressor, Toprol XL) and propranolol (Inderal LA).

Taste changes

Some blood pressure medications, some antibiotics, and the diabetes drug metformin can alter your sense of taste. "People often report a metallic taste," says Mehta. Or it might be a bitter taste or a sense that food tastes slightly off. Ask your doctor for help; the problem may go away if you're able to take a different dose of the medication or switch to another drug.

The blood pressure medications that are most likely to cause taste changes are in the class of ACE inhibitors and include lisinopril (Zestril) and captopril. Among antibiotics, metronidazole (Flagyl) and clarithromycin have been linked to taste changes.

Gum overgrowth

Some drugs can cause extra gum tissue to form (gum overgrowth). This makes it difficult to brush your teeth and increases the risk of gum disease.

Culprits here include blood pressure drugs in the class of calcium-channel blockers, such as nifedipine (Procardia) and amlodipine (Norvasc). "Studies show that 10% to 30% of people who take nifedipine have gum overgrowth, and some research reports much higher rates," says Mehta.

Other drugs with this possible side effect are the seizure medication phenytoin (Dilantin) and the immune suppressant cyclosporine (Gengraf, Neoral), used for people who have certain autoimmune diseases or who have had an organ transplant.

Oral fungal infections

Thrush, a fungal infection of the mouth, can occur with medications used for asthma and chronic obstructive pulmonary disease (COPD). These include inhaled steroids such as fluticasone (Advair) and budesonide (Airsupra, Breyna, others) and the oral steroid prednisone. Drugs that suppress the immune system, such as tacrolimus (Astagraf XL, Envarsus XR, others) and cyclosporine, can also cause oral thrush.

White patches on the tongue are a sign of thrush. "About 5% to 10% of people who use inhaled steroids develop thrush, depending on the dose and their oral hygiene," says Mehta.

Protect your oral health

Many people take several medications, and drug interactions can compound the side effects of each. "If you take two drugs that can cause dry mouth, the effect may be significantly magnified rather than just doubled, making dry mouth more noticeable and problematic," says Mehta.

If something feels different in your mouth for more than a few days, talk to your health care provider or pharmacist. Mehta also recommends reviewing your medications with your clinician at least once a year to catch any potential problems. It's also important to practice good oral hygiene, keep up with regular visits to the dentist, and inform your dentist of all medications you take.

Image: © Lock Stock/Getty Images