Common over-the-counter medicines are linked to cognitive impairment in elderly people, shows studyBMJ 2016; 353 doi: https://doi.org/10.1136/bmj.i2220 (Published 19 April 2016) Cite this as: BMJ 2016;353:i2220
Anticholinergic drugs found in many commonly used over-the-counter medicines, such as night time cold remedies, are associated with brain scan changes linked to cognitive impairment in older people, a study in JAMA Neurology has shown.1
Previous research had found that anticholinergic drugs were associated with an increased risk of cognitive impairment and dementia. Researchers investigated the potential mechanism of this link by analysing brain scans in 451 cognitively normal older people (mean age 73.3 years) taking part in two US national research programmes: the Alzheimer’s Disease Neuroimaging Initiative and the Indiana Memory and Aging Study. Sixty (13%) of the study participants were taking at least one drug with medium or high anticholinergic activity.
Cognitive and memory tests showed that patients taking anticholinergic drugs had lower mean scores in tests of short term memory and executive function than those not taking those drugs. Their mean score on the Wechsler Memory Scale revised logical memory immediate recall test was significantly lower than in people not on anticholinergics (mean score 13.27 versus 14.16; P=0.04), as was their executive function composite score (0.58 versus 0.78; P=0.04).
Results from positron emission tomography (PET) scanning showed reduced glucose metabolism, a biomarker for brain activity, in the brain as a whole among people taking anticholinergics (raw mean uptake of fluorodeoxyglucose 1.48 versus 1.52; P=0.03). Activity was also reduced in the hippocampus, a brain region associated with memory, which has previously been shown to be affected early in Alzheimer’s disease.
Magnetic resonance imaging (MRI) showed considerable associations between brain structure and anticholinergic drug use. People taking anticholinergics had smaller total cortical volume and larger ventricles than those who did not.
“These findings provide us with a much better understanding of how this class of drugs may act upon the brain in ways that may raise the risk of cognitive impairment and dementia,” said Shannon Risacher, lead researcher, from Indiana University Health’s Neuroscience Center in Indianapolis, USA. “Given all the research evidence, physicians might want to consider alternatives to anticholinergic medications if available when working with their older patients.”