A new study by U.S. researchers has found that common, over-the-counter drugs - including those to promote sleep and treat allergies - may increase the risk of dementia and Alzheimer’s disease among people 65 and older.
The drugs are called anticholinergics, a class of medications that block the neurotransmitter acetylcholine. They are found in a host of medicines ranging from antidepressants to muscle relaxants.
They cause a host of side effects, including dry eyes and mouth, sleepiness and constipation.
A study of the drugs found a higher risk of dementia among older adults who took anticholenergics for three years or more.
Researchers at the University of Washington School of Pharmacy followed almost 3,500 older men and women, none of whom appeared to suffer from dementia or Alzheimer’s at the outset of the study.
Eight hundred of the participants who took standard daily doses of drugs - including antihistamines and drugs for bladder control - developed dementia, including Alzheimer's, after an average follow-up of seven years.
The increased risk of dementia was also seen among those who took medications - including tricyclic antidepressants - to treat depression.
Investigators say people should not panic and stop taking their medications.
Rather, they advise those who take suspect drugs should talk to their health care providers, who may be able to prescribe safer alternatives.
The study was published in the journal JAMA Internal Medicine.