UK researchers have found a link between the long-term use of certain anticholinergic drugs and an increased risk of dementia. The findings are published in the British Medical Journal.
The researchers looked at drugs which have an ‘anticholinergic’ action – meaning they block the action of a brain chemical called acetylcholine, which is used to help nerve cells send signals to one another. Some of the symptomatic treatments for Alzheimer’s disease work by boosting levels of this chemical, and some previous research has linked the use of anticholinergic drugs to an increased risk of dementia
Researchers compared the medical records of over 40,000 people between the ages of 65 and 99 who received a dementia diagnosis, with over 280,000 people who did not develop dementia. They found that people who had been prescribed anticholinergic drugs to treat depression, urological conditions, or the symptoms of Parkinson’s disease were slightly more likely to have developed dementia. They did not find any link between dementia risk and anticholinergic drugs that are used to treat other conditions such as allergies or stomach problems.
They found evidence for the link even if people had been using the drugs 15-20 years before being diagnosed with dementia, and after taking into account dementia risk factors, such as heart disease and diabetes. Researchers only included people in their analysis if they had been taking anticholinergic drugs for over a year.
Dr Carol Routledge, Director of Research at Alzheimer’s Research UK, said:
“This well conducted study adds to existing evidence of a link between certain anticholinergic drugs and an increased risk of dementia. By taking advantage of high-quality medical information held in GP records, researchers were able to analyse data from hundreds of thousands of people and drill down into important details, such as when people started to take these drugs, the strength of their anticholinergic effect, and which conditions they were being prescribed for.
“While the results don’t paint a straightforward picture, they do reveal a link between dementia risk and the use of certain drugs that may be prescribed to treat depression, urological conditions or the symptoms of Parkinson’s disease. Not everyone with the conditions highlighted in the study will be prescribed these particular drugs, and the researchers did not find a link between dementia risk and anticholinergic drugs used to treat allergies, stomach problems or muscle spasms.
“While there are important advantages to research that uses the rich data held in medical records, we know that less than 70% of people with dementia receive a formal diagnosis, and this study may not tell the whole story. The study didn’t investigate what might cause this link between anticholinergics and dementia risk, and researchers will need to build on these findings in future studies.
“Anticholinergics can have many beneficial effects which doctors need to weigh against any potential side effects. Anybody concerned about their current medication should speak to a doctor before stopping a course of treatment.”