Common Over-the-Counter Medicines Linked to Dementia in New Study

Ingredient in Benadryl linked to dementia, study shows.

The link has been studied before but this is an especially good study, said Dr. James Leverenz, a neurologist who directs the Cleveland Center for Brain Health at the Cleveland Clinic and was not party of the new study.

Still, he stressed the researchers only found an association between the drugs and dementia and did not determine whether the drugs caused dementia. More research is needed, he said, adding that some antihistamine products have fewer effects on the cholinergic system of the brain, which is involved in thinking skills and memory. He said this link between dementia and these drugs has not been studied in younger adults.

"Consult with your primary clinician if you have questions," he said. "Carefully read the contents of medications you take over the counter."