Common Cold & Flu Medicines May Shrink Brain, Up Dementia Risk- Study

Taking a pill.

People who become sick with the flu, fever or allergy generally take over-the-counter cold, cough or heartburn medication. But this is a very common, and potentially harmful mistake, warns a new study.

People, specifically older adults, should avoid taking common over-the-counter medicines as those medicines may shrink their brain and raise their risk for dementia, caution scientists at Indiana University School of Medicine.

The study came up with the warning after a link was found between the medicines and memory detriment, brain damage and problems in thinking

In their study, the Indiana scientists found that two of the key ingredients ‘promethazine’ and ‘diphenhydramine’ widely used in these medicines were causing a reduction in brain functioning and smaller brain sizes.

The study says that a class of drugs called anticholinergics, are linked to mental impairment and increased risk for dementia through brain imaging. The common anticholinergic drugs include certain over-the-counter and prescription drugs, like Benadryl, Tylenol PM and Advil PM, Demerol, Dimetapp, Dramamine, Paxil, Unisom, VESIcare etc.

The findings demonstrated lower metabolism and smaller brain sizes among the group of participants taking anticholinergic drugs.

This is not the first time researchers have established a link between anticholinergic drugs and shrinkage in the brain, memory problems and decreased brain metabolism, but the new study is believed to be the first to offer an insight into the underlying biology of clinical links established in earlier research using neuroimaging measurements of brain metabolism and atrophy. They said Anticholinergic drugs block the neurotransmitter acetylcholine (the chemical used in the transmission of electrical signals) in the brain.

“These 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,” said lead author of the new study Shannon Risacher, who’s an assistant professor of radiology and imaging sciences at Indiana University School of Medicine.

To come up with their conclusion, Risacher and colleagues examined a group of 451 older people with an average age of 73 and who had normal brains.

After analysing the results of participants’ memory tests, their MRI brain scans and other neuroimaging data, the researchers found that those taking the drugs which contained promethazine and diphenhydramine performed worse on short-term memory tests than those who did not take the drugs. They also did worse on tests of executive function, including problem solving and planning than their counterparts.

Although the research offer compelling evidence that common cold and flu medicines can cause cognitive impairment, the researchers acknowledged more research is needed to determine exactly how the mechanisms involved, and and what dosage and for how long use of these medicines could lead to changes in brain.

“I certainly wouldn’t advise my grandparents or even my parents to take these medications unless they have to,” says Risacher. “I’d suggest that doctors monitor medications and their effects, and to use the lowest dose that’s effective.”

The latest study findings were published in JAMA Neurology.