Common drugs, such as Benadryl and Dimetapp, could be harming the brains of seniors, a new study has found.

Prolonged use of certain drugs called anticholinergics is linked to physical changes in the brain, according to Shannon Risacher, an assistant professor of radiology and imaging at the Indiana University School of Medicine

“The concern is that taking these drugs may increase your risk of dementia,” Risacher says. “Particularly in people with a family history of dementia.”

Anticholinergics stop a chemical called acetylcholine from working properly in the nervous system, which can help ease gastrointestinal, respiratory or urinary symptoms, for example.

Gravol, sleep aid Unisom, antidepressant Paxil and antipsychotic Zyprexa are among the drugs in this class. A full list of anticholinergics can be found here.

“Older adults who might be at risk of dementia, or who feel their memory has started to change might want to go see their doctors if they are on these medications,” Risacher says.

Researchers examined brain scans and cognitive test results from 451 older adults, including 60 who had been taking anticholinergic drugs for at least a month.

The researchers noted clear differences among those taking anticholinergics.

“Over a long period time, using these drugs may be really bad for your brain in a very concrete way,” says Sandra Black, a senior scientist at Sunnybrook Research Institute.

Researchers noted reduced brain volume, as well as thickness in areas linked to cognitive function. They also saw lower levels of glucose processing in the brain and lower scores on memory tests.

Black says those taking the drugs long-term should be aware of the potential risks.

“That’s very important because they are avoidable,” she says. “There are alternatives.”

Michael Borrie, a geriatrician and researcher with Lawson Research Institute in London, Ontario, says these types of drugs simply aren’t good for older people to take.

“This study shows memory is not as good, brain activity is impaired and it showed that there was shrinkage of the brain related to memory,” Borrie says.

Borries says pharmacists need to be attentive to products people are purchasing over the counter.

“We also need to get physicians to stop prescribing these medications,” Borrie added.

With a report from CTV’s medical specialist Avis Favaro and producer Elizabeth St. Philip