A study by US researchers has linked prolonged use of certain widely available over-the-counter medicines with an increased risk of dementia.
The medicines implicated – which include popular hayfever and allergy tablets such as Benadryl and Piriton, sleeping pills like Nytol and and asthma drugs – are a class of drugs known as anticholinergics. They work by blocking acetylcholine, a chemical involved in the transmission of electrical impulses between nerve cells. People with Alzheimer’s disease are known to have low levels of acetylcholine and the concern is that medicines containing the chemical may exacerbate or even trigger the problem.
The researchers, from the University of Washington, fear that long-term use of these medicines – common among older people – could lead to structural change in the brain.
Although earlier studies have raised raised concerns that anticholinergic drugs may cause mental impairment in the elderly, the latest research is the first to show a dose response linking greater use of the medicines with an increasing risk of dementia.
Researchers studied 3,434 people aged 65 and over for around seven years, monitoring their use of anticholinergic drugs. They discovered that those taking the highest doses of anticholinergic drugs over the study period, experienced a 54% increased risk of developing dementia, compared to non-users.