Memory & Medication: Balancing Benefits and Risks

by Taeh A. Ward, PhD


Research shows that some commonly used prescription and non-prescription medications have the potential to negatively impact our thinking abilities. These medications are described as “anticholinergic,” because they block a chemical in the brain called acetylcholine, which plays an important role in learning and memory.

As acetylcholine concentrations decrease with normal aging, older individuals are especially vulnerable to medications with anticholinergic properties. These medications are often used to treat: seasonal allergies, sleeping problems, nausea, motion sickness, intestinal cramps, bladder leakage/incontinence, seizure disorder, cardiovascular disease, chronic obstructive pulmonary disease, depression, anxiety and other psychiatric symptoms. As older individuals are more likely to experience these difficulties, they are more likely to take medications that can affect memory. An estimated 8 to 37 percent of older adults use anticholinergic medications.

Recent studies demonstrate that taking medication with strong anticholinergic effects for as little as 60 days may double the risk of cognitive impairment in older individuals. While this effect is often considered reversible if the medication is discontinued, some research suggests that use of anticholinergic medications for more than three years is associated with greater risk for dementia.

There is evidence to suggest that anticholinergic medication reduces activity in the brain, contributing to greater shrinkage of the brain and memory difficulties. However, this depends on how strongly the medication affects chemicals in the brain and how long the medication is taken.

In addition, there are other commonly used medications that can increase the risk for impaired memory and other thinking difficulties. For example, recent studies show that medication used to treat heartburn called protein pump inhibitors (PPI) are associated with an increased likelihood of developing dementia over time. These medications appear to increase the buildup of a protein in the brain associated with Alzheimer’s disease, and they can also cause vitamin B-12 deficiency.

Many over-the-counter medications can impact memory as much or more than prescription medications. Benadryl, and any medication containing diphenhydramine, appears to have strong anticholinergic effects. When people take more than one anticholinergic medication, they are also more likely to experience memory impairment. An older individual treated for an overactive bladder and difficulty sleeping may potentially take two or more medications that may impact memory.

If you have concerns regarding possible memory difficulties or learn that you are taking medications that can impact your memory, it is important to consult with your physician. Do not discontinue the use of any medication without consulting with your doctor. Remember that many of the medications described above could potentially affect your thinking abilities but also improve symptoms that can affect your quality of life.

It may be helpful to ask your doctor if there is a similar treatment that may be just as beneficial for symptom reduction but has a lower risk for memory difficulties. Long-term use of over-the-counter sleep-aids containing diphenhydramine may pose a greater risk for memory difficulties than use of melatonin and cognitive-behavioral therapy for insomnia. It is important to carefully weigh the potential risks and benefits of any treatment by consulting with your doctor.

For a list of the most common medications with anticholinergic effects, visit


Dr. Ward, a clinical neuropsychologist at Pinehurst Neuropsychology, can be reached at or 910-420-8041.