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Research Highlights

Nearly 14% of older adults with dementia are prescribed a combination of medicines affecting the central nervous system

About 14% of older adults with dementia filled prescriptions for multiple medications that target the central nervous system (CNS), or the brain and spinal cord, according to a recent study. The use of multiple medications, called polypharmacy, can increase the risk of serious side effects. Taking combinations of CNS-active drugs can lead to an increased risk of falling, breathing issues, and heart problems. In addition, some CNS-active drugs can affect thinking and memory — a side effect that is especially troubling in people with dementia. The NIA-supported study, led by researchers at the University of Michigan, was published in JAMA on March 9.Nurse giving an older adult medications.

Medications affecting the CNS are used to treat depression and other mental health conditions, prevent seizures, and reduce pain. Older adults who have dementia sometimes have behavioral and psychological symptoms, such as agitation or delusions. Health care providers may prescribe CNS-active drugs to treat those symptoms, but evidence of the drugs’ effectiveness for the symptoms is limited.

To better understand how many people with dementia received a combination of these drugs, researchers looked at Medicare claims data on more than 1 million adults ages 77 to 88 who had dementia. The researchers analyzed the number and timing of prescriptions filled to estimate the number of people who likely took combinations of the drugs.

The researchers found that 13.9% of these adults filled prescriptions for three or more CNS-active drugs for more than 30 days in a row. More than half of those adults had the drugs for more than 180 days. The researchers also found that people who were prescribed a combination of CNS-active drugs had higher rates of insomnia, mental health conditions, and pain not associated with cancer and seizure disorders. However, the researchers could not, based on the claims data, determine whether the drugs were prescribed to treat those conditions.

The researchers identified some limitations of their study that could point to areas for further investigation. The study may have overestimated the number of people who actually took the drugs because it counted prescriptions filled. The study did not look at the reasons the drugs were prescribed or their dosages. It also did not determine whether the adults who took a combination of CNS-active drugs had health problems that the drugs could cause, such as falls.

This study is the first to examine the number of adults with dementia who live in the community — not in nursing homes — and take a combination of CNS-active drugs. As the number of adults living with dementia increases, better understanding how these drugs are used, their effects, and associated risks could help health care providers and dementia patients make safer, well-informed care decisions.

This research was supported by NIA grant R01AG056407.

These activities relate to NIH’s AD+ADRD Research Implementation Milestone 1.B, “Quantify the exposome in existing and new AD cohorts to gain a more precise measure of environmental exposure factors and their relationship to AD risk and individual trajectories of disease progression,” and 13.K, “Expand research leading to understanding of effectiveness and impacts of non-residential and residential care of PWD.”

Reference: Maust DT, et al. Prevalence of central nervous system-active polypharmacy among older adults with dementia in the US. JAMA. 2021;325(10):952-961. doi: 10.1001/jama.2021.1195.

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