New research shows that a medication taken by hundreds of thousands in Britain could increase the risk of dementia.
Anticholinergics are the medication in question which are prescribed to reduce over-active bladders.
The medication works by reducing the activity of certain muscles to stop the bladder contracting, reports the Daily Mail.
This helps stop the spasms that can cause incontinence and the need to urinate frequently.
New research shows nearly one million Brits on these medications have an increased dementia risk by about a third.
The research compared around 170,000 patients in England over the age of 55 with dementia with 800,000 patients without dementia.
It concluded that taking an anticholinergic was linked to an 18% increase in dementia diagnosis.
The study also found that the higher risk was more likely in men, with 22% compared to only 16% in women.
Researchers analysed different types of drugs and found that some carry a higher risk. For example, those taking oxybutynin hydrochloride had a 31% higher risk of dementia.
Experts have said there is a need to consider alternative medications for over active bladders in older patients.
The research was published in the British Medical Journal, it said that not all anticholinergics are linked to an increased chance of dementia.
For example, these include darifenacin, fesoterodine fumarate, flavoxate hydrochloride, propiverine hydrochloride, and trospium chloride.
Limitations of the study included several elements. For example, the exact dosage given to patients was lacking meaning the authors couldn’t fully explore if higher doses of some drugs led to an increased risk of dementia over time.
Another was the data relied on patient records which may have been unreliable or incomplete.
Other studies have linked some forms of anticholinergic to dementia with experts urging doctors to consider later life impacts.