A common class of drugs that doctors prescribe for a number of conditions — from bladder problems to Parkinson’s disease and depression — may increase a person’s dementia risk, a large new study concludes.
A study published in the journal JAMA Internal Medicine on Monday suggests that the link for dementia risk is strongest for certain classes of anticholinergic drugs – particularly antidepressants such as paroxetine or amitriptyline, bladder antimuscarinics such as oxybutynin or tolterodine, antipsychotics such as chlorpromazine or olanzapine and antiepileptic drugs such as oxcarbazepine or carbamazepine.
The risk is only associated with 1,095 daily doses within a 10-year period, which is equivalent to an older adult taking a strong anticholinergic medication daily for at least three years.
This kind of dosage of these drugs resulted in “50% increased odds of dementia,” the research study said.
For their study, lead researcher Prof. Carol Coupland and team analysed the medical records of 58,769 people with dementia and 225,574 people without dementia. They were all 55 years old or above at baseline.
Among those with dementia, 63% were women and the average age was 82. For each person with dementia, the researchers found five control matches of the same age and sex and who attended the same general practice to receive medical care.
“The study is important because it strengthens a growing body of evidence showing that strong anticholinergic drugs have long term associations with dementia risk,” said Prof. Coupland, professor of medical statistics in primary care at the University of Nottingham in the United Kingdom.
“It also highlights which types of anticholinergic drugs have the strongest associations. This is important information for physicians to know when considering whether to prescribe these drugs,” she told CNN. “This is an observational study so no firm conclusions can be drawn about whether these anticholinergic drugs cause dementia.”
The study warns people against stopping any of the medications listed without consulting their doctors.