A study has found that over-the-counter sleeping aids and hay fever treatments can increase the risk of Alzheimer's Disease, reports The Guardian. The sleeping medication Nytol and anti-allergy pills Benadryl and Piriton all belong to a class of drug highlighted in a warning from researchers.
Each of these drugs has "anticholinergic" blocking effects on the nervous system that are said – at higher doses – to raise the likelihood of developing Alzheimer's and other forms of dementia significantly over several years. Other drugs on the risk list include older "tricyclic" antidepressants such as doxepin, and the bladder control treatment Ditropan (oxybutynin). Many of these medicines are taken by vulnerable older people, according to the scientists, who say their findings have public health implications.
Anticholinergic drugs block a nervous system chemical transmitter called acetylcholine, which can lead to side-effects including drowsiness, blurred vision and poor memory. People with Alzheimer's disease are known to lack acetylcholine. The leader of the US study, Professor Shelly Gray, director of the geriatric pharmacy programme at the University of Washington School of Pharmacy, said: "Older adults should be aware that many medications – including some available without a prescription, such as over-the-counter sleep aids – have strong anticholinergic effects. And they should tell their healthcare providers. Of course, no one should stop taking any therapy without consulting their healthcare provider. Healthcare providers should regularly review their older patients' drug regimens – including over-the-counter medications – to look for chances to use fewer anticholinergic medications at lower doses."
Previous research has raised concerns about the use of anticholinergic drugs and mental impairment in the elderly. But the new study is the first to show a dose response linking greater use of the medicines with an increasing risk of dementia.
The scientists tracked the health of 3,434 men and women aged 65 and over for around seven years while monitoring their use of anticholinergic drugs. Of those, 637 developed Alzheimer's and 160 were afflicted by other forms of dementia. For those taking the highest doses of anticholinergic drugs over the study period, the relative risk of dementia was increased by a statistically significant 54% compared with no use. The risk of Alzheimer's alone was raised by 63%.
The findings showed that people taking at least 10mg per day of doxepin, 4mg per day of diphenhydramine (Nytol, Benadryl) or 5mg per day of oxybutynin (Ditropan) for more than three years were at an increased risk of developing dementia. Available substitutes that did not have anticholinergic effects included selective serotonin re-uptake inhibitor (SSRI) antidepressants such as Prozac and newer anti-histamine allergy treatments including loratadine (Claritin), said Gray. She added: "If providers need to prescribe a medication with anticholinergic effects because it is the best therapy for their patient, they should use the lowest effective dose, monitor the therapy regularly to ensure it's working, and stop the therapy if it's ineffective."
[link url="http://www.theguardian.com/society/2015/jan/27/sleeping-drugs-increased-risk-alzheimers"]Full report in The Guardian[/link]
[link url="http://archinte.jamanetwork.com/article.aspx?articleid=2091745"]JAMA Internal Medicine abstract[/link]