People over age 65 who frequently take over-the-counter sleep aids and certain other commonly used drugs may be increasing their risk of dementia, new findings show.
In the study, the researchers looked at drugs that have "anticholinergic effects," meaning they block a neurotransmittercalled acetylcholine. Many drugs fall into this class, including tricyclic antidepressants such as doxepin, antihistamines like Chlor-Trimeton (chlorpheniramine) and drugs like Detrol (oxybutinin) used to treat overactive bladder.
"We have known for some time that even single doses of these medications can cause impairment in cognition, slower reaction time, [and] reduced attention and ability to concentrate," said Shelly Gray, the study's first author and a pharmacy professor at the University of Washington in Seattle. Originally, "the thinking was that these cognitive effects were reversible when you stopped taking the medication."
But Gray's study found a link between heavier use of these medications and dementia, "which is a nonreversible, severe form of cognitive impairment," she said.
All medicines can have side-effects and anticholinergic-type drugs that block a neurotransmitter called acetylcholine are no exception.
Patient information leaflets accompanying such drugs warn of the possibility of reduced attention span and memory problems as well as a dry mouth.
But researchers say people should also be aware that they may be linked to a higher risk of developing dementia.
Dr Shelly Gray and colleagues from the University of Washington followed the health of 3,434 people aged 65 and older who had no signs of dementia at the start of the study.
They looked at medical and pharmacy records to determine how many of the people had been given a drug with an anticholinergic effect, at what dose and how often and compared this data with subsequent dementia diagnoses over the next decade.