A common kind of prescription and over-the-counter medication, including some cold medicines, has been linked to cognitive impairment in older adults, finds a new study published in JAMA Neurology.
Shannon Risacher, assistant professor of radiology and imaging sciences at Indiana University School of Medicine and first author of the new paper, and her colleagues analyzed already existing data from 451 people around ages 70-75 who had normal brains. They examined the results of memory tests, MRI brain scans and other neuroimaging data—all while paying particular attention to people who said they took anticholinergic drugs. These include certain over-the-counter drugs, like Benadryl, Tylenol PM and Advil PM, according to the researcher, along with prescribed medications like some antidepressants, motion sickness medications and bladder control drugs. Anticholinergic drugs block the neurotransmitter acetylcholine in the brain.
The researchers found that older people who regularly took at least one anticholinergic drug showed poorer cognition, lower brain volumes and less glucose metabolism in the whole brain and the temporal lobe, which is important for memory, than people who didn't report taking this kind of medications. The link persisted even after the team controlled for the number of medications the people in the study were taking.
Previous research has linked anticholinergic medications to cognitive impairment and worsened memory, the paper points out. More research is needed to determine exactly how these effects might be linked to the drug, and what dosage and duration may be associated with brain changes.
“I certainly wouldn’t advise my grandparents or even my parents to take these medications unless they have to,” says Risacher. Many anticholinergic drugs, like antihistamines and antidepressants, have alternatives.
“I’d suggest that doctors monitor medications and their effects, and to use the lowest dose that’s effective.”