A new study has found that over-the-counter sleeping aids and anti-allergy medicines can increase the risk of Alzheimer’s disease.
The sleep medication Nytol and anti-allergy drug Benadryl are among the drugs 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, The Guardian reports. Other drugs on the researchers’ list include “tricyclic” antidepressants and the bladder control treatment drug Ditropan (oxybutynin). Many of these medicines are taken by vulnerable older people.
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 Guardian reports. Professor Shelly Gray, director of the geriatric pharmacy program at the University of Washington School of Pharmacy, who led the study, 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.”
In their study, the researchers 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 developed 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 percent compared with no use. The risk of Alzheimer’s alone was raised by 63 percent, according to the Guardian.
People taking at least 10 mg per day of doxepin, 4 mg per day of diphenhydramine (Nytol, Benadryl) or 5 mg per day of oxybutynin (Ditropan) for more than three years were at an increased risk of developing dementia. The study was published in JAMA Internal Medicine.
Gray said, “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,” according to the Guardian.