Starting certain medications may lead to faster memory loss in older adults

Medicines designed to help with chronic health conditions may speed memory loss in older adults, a University of Florida researcher and his colleagues report.

Kenneth Heilman, M.D., a distinguished professor of neurology at the UF College of Medicine and UF’s McKnight Brain Institute, recently co-authored a study published in the journal PLOS ONE showing that older people who begin regularly taking medications called anticholinergics experience a more rapid rate of cognitive decline than those who do not.

Anticholinergics are most commonly used in painkillers, antidepressants, overactive bladder medications and antihistamines. They block acetylcholine, a neurotransmitter that plays a crucial role in learning and memory, either directly or — more often ­— indirectly as a side effect.

Prior studies have shown a connection between the prevalent use of anticholinergic medications and impaired cognitive function, such as memory loss, in older people. Heilman and colleagues sought to discover at what rate the initiation of these medications affects the same population.

They used data from the Religious Orders Study, a longitudinal study conducted at Rush University Medical Center in Chicago with more than 1,100 participants composed of older religious clergy. The participants were screened for dementia at enrollment and underwent annual medical and psychological evaluations. The data, which were collected for an average of 10 years, detail participants’ global cognitive functioning, medical histories and medications.

For the anticholinergic study, approximately 1,000 of the participants were separated into three groups: those who routinely used one or more anticholinergic medications, those who didn’t report using any during the study, and those who started to take an anticholinergic medication after the study began.

The researchers found that participants who began using the medication during the course of the study had a steeper decline in cognitive functioning than those who had never used the medication. Notably, they also started to decline 2.9 times faster than they were prior to taking the drugs.

“We thought the chronic users would be the most impaired, but they weren’t — it was the people who began using the medications after enrolling in the study,” said Heilman, director of the Memory and Cognitive Disorder Clinics.

While the reason for this is unknown, it’s possible that chronic users, who started taking these medicines earlier in their lives, had an easier time acclimating to the effects over a longer period, he said.

While many over-the-counter drugs that treat conditions such as allergies, incontinence and abnormal heartbeat are anticholinergics, some are stronger than others. Patients should ask their physicians or pharmacists if the medications they’re taking have strong anticholinergic properties, Heilman said.

“The effect on memory, of course, is variable, as well as the degree of impairment,” said senior author Capt. Jack Tsao, M.D., D.Phil., a professor of neurology at the Uniformed Services University of the Health Sciences in Bethesda, Md. “If you’re having trouble remembering things and are taking a medication with anticholinergic effects, you should talk with your doctors about switching to another medication or stopping the medication. If your memory loss is a result of using the medication, it’s possible that discontinuing it could reverse any memory impairment.”

If funding is secured, the next step in the team’s research efforts would be to quantify pathological changes in the brains of participants who took anticholinergic medications, said Tsao, the director of Traumatic Brain Injury Programs for the U.S. Navy Bureau of Medicine and Surgery. They also would like to study if there is any association between using these types of medications and subsequently developing Alzheimer’s disease. Lastly, they would like to perform memory testing on participants of different ages before and after they start anticholinergic medications.

“What would happen in a population from early adulthood, throughout their lives?” Heilman said. “Does the amount of these medications people take have an overall adverse effect on them over time, cognitively? This study couldn’t answer that, but it may be very important.”