|
 The drugs, known as anticholinergics, stop a chemical called
acetylcholine from working properly in the nervous system. By doing
so, they can relieve unpleasant gastrointestinal, respiratory or
urinary symptoms, for example.
The list of such drugs is long. Among them: Benadryl for allergies,
the antidepressant Paxil and the antipsychotic Zyprexa, Dimetapp for
colds and the sleep aid Unisom.
In the new analysis, researchers looked at brain scans and cognitive
test results from 451 older adults – including 60 who had been
taking anticholinergic drugs for at least a month. The study
participants were about 73 years old on average.
None of them had been diagnosed with cognitive problems like
Alzheimer’s disease or dementia.
But brain scans of people who used anticholinergic drugs showed
lower levels of glucose processing in the brain – an indicator of
brain activity – in a region of the brain associated with memory
that’s also affected early in the course of Alzheimer’s disease.
In addition, patients who used these medications had reduced brain
volume and thickness in some regions linked to cognitive function,
the researchers report in JAMA Neurology.
People who used these drugs also scored lower on tests of immediate
memory recall and executive function compared to people who weren’t
using these drugs, researchers found.
“There are definitely medical benefits to all of the anticholinergic
medications we looked at, which could outweigh the cognitive risks,”
said lead study author Shannon Risacher of the Indiana Alzheimer
Disease Center at the Indiana University School of Medicine in
Indianapolis.
“But if alternative therapies are available that provide effective
treatment of these conditions, patients and doctors might want to
consider avoiding anticholinergic medications,” Risacher added by
email.
The study can't prove the anticholinergics were the cause of
participants' brain and memory differences.
The authors also acknowledge limitations of their study. In addition
to the small number of participants taking anticholinergic drugs,
another problem is that the study relied on participants to
accurately recall and report on drug use, which wasn’t verified by
medical records or prescription data.
[to top of second column] |
This study and others like it are limited as well by a lack of
specifics about what dosage of anticholinergic drugs people took or
how long they used the medications, noted Alain Koyama, an outcomes
researcher at Health Advocate, a consultancy in Los Angeles.
“Therefore, it is yet unclear if lower doses or shorter durations of
use can in fact mitigate risk of cognitive harm,” Koyama, who wasn’t
involved in the study, said by email.
Still, the study adds to a growing body of evidence connecting
anticholinergic medicines to cognitive problems later in life and
offers new evidence to explain why this link exists, Koyama added.
The findings should encourage doctors and patients to discuss the
drugs, and to consider whether the potential risk of cognitive
decline merits avoiding or limiting use of these medicines.
Not every patient will arrive at the same answer, however.
“Since the pathology underlying any effect of anticholinergic drugs
on cognitive function likely takes years to manifest, if a patient
is clearly benefiting from a drug in the short-term, but may not
survive in the long term, any cognitive harm from the drug may be
inconsequential,” Koyama said.
“On the other hand, a healthier patient particularly concerned about
future dementia risk, whether because of family history or other
reason, may consider alternative treatments,” Koyama added.
SOURCE: http://bit.ly/1WcH6Dt JAMA Neurology, online April 18, 2016.
[© 2016 Thomson Reuters. All rights
reserved.] Copyright 2016 Reuters. All rights reserved. This material may not be published,
broadcast, rewritten or redistributed.
 |
