Some widely used drugs available both over-the-counter and by prescription could be linked to the development of dementia and Alzheimer’s disease in older adults, according to a new study.
The researchers believe they have found a link between the prolonged use of drugs including certain hay fever, incontinence treatments, sleep medications and anti-depressants and reduced brain size, the (U.K.) Independent reports. The drugs—known as anticholinergics—block the chemical that transfers electrical impulses between nerves, and they were also found to lower metabolism.
A team at the Indiana University School of Medicine led the research. They used brain-imaging techniques and cognitive tests to assess the 451 elderly study participants. Sixty were taking at least one medication with an anticholinergic agent, according to the Independent. The researchers found that people taking such drugs had notably reduced brain volume, and larger ventricles and cavities inside the brain. They exhibited poorer performance in short-term memory tasks, verbal reasoning, planning and problem-solving. The anticholinergic drug users also had lower levels of glucose metabolism in their brain, which is a biomarker for brain activity that leads to Alzheimer’s.
Dr. Shannon Risacher, assistant professor of radiology and imaging sciences at Indiana and first author of the paper, said the “findings provide us with a much better understanding of how this class of drugs may act upon the brain in ways that might raise the risk of cognitive impairment and dementia . . . physicians might want to consider alternatives to anticholinergic medications if available when working with their older patients.”
Earlier research has linked these drugs have been linked to cognitive impairment and increased dementia risks, but this study is believed to be the first to look at the underlying biology by measuring brain metabolism and atrophy through neuroimaging, according to the Independent. Dr. Risacher said the findings might contain “clues to the biological basis for the cognitive problems associated with anticholinergic drugs.” But additional studies are needed in order to “truly understand the mechanisms involved.”
The researchers concluded, “use of [anticholinergic] medication among older adults should likely be discouraged if alternative therapies are available.” But Dr. James Pickett, head of research at the Alzheimer’s Society, warned against drastic action. “This small study takes a closer look at changes in the structure and activity of the brain. However, the full impact of these drugs remains unclear as the people taking them in this study were more likely to have insomnia, anxiety, or depression, all of which are risk factors for dementia.” Pickett said doctors need to know more about possible effects of these drugs, but he thought doctors and pharmacists should be aware of the potential link when they consider treatments for older individuals. He advises patients to consult a doctor before stopping any medications.