Sleep Remedies, Hay fever & Overactive Bladder Drugs could increase Alzheimer’s risk

Photograph: Boston Globe/Getty Images

Photograph: Boston Globe/Getty Images

Researchers have found a link between people who have taken popular sleep remedies, hay-fever and overactive bladder drugs, with an increased risk of developing Alzheimer’s disease.

 Medicines that could increase Alzheimer’s risk

The medicines involved belong to a class known as anticholinergic drugs, which are present in the antihistamines Benadryl and Piriton and the sleep remedy Nytol. They are also found in some older types of anti-depressants and medications for bladder control such as Ditropan and Lyrinel XL.

The way these drugs work is to block acetylcholine, which is an important messenger to the brain, as it has a range of functions within the body.


The study was carried out by researchers at the University of Washington, and published in JAMA International Medicine. It collected data from 3,434 men and women aged over 65 for seven years, whilst at the same time recording their use of certain anticholinergic drugs.

The study found that the risk of developing dementia was increased when a higher dose was taken over several years:

  • At least 10 milligrams(mg) per day of the antidepressant doxepin,
  • Four mg per day of diphenhydramine (Nytol, Benadryl) or
  • Five mg per day of oxybutynin (Ditropan) for overactive bladder

But experts say that it is important for people to not just stop taking their medication if they are worried about possible side effects.

Lead study Professor, Shelly Gray suggested that instead doctors should review the prescriptions of their older patients and look to prescribing more modern medication:

“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 studies had already linked anticholinergic drugs with onset of dementia in the elderly, but this is the first new study to show that the higher the dose, the higher the risk of dementia. In fact, the research showed that those taking the biggest doses were at 54% higher risk than those who took none, with the risk of Alzheimer’s at 63% higher.

Dr Simon Ridley, of Alzheimer’s Research UK, believes that more research is needed, adding:

“This large study adds to some existing evidence linking anticholinergic drugs to a small increased risk of dementia, but the results don’t tell us that these drugs cause the condition.”

Other experts in the field of dementia agree with him. Dr Doug Brown, director of research and development at the Alzheimer’s Society UK, said:

“… it is still unclear whether this is the case and if so, whether the effects seen are a result of long-term use or several episodes of short-term use.  More robust research is needed to understand what the potential dangers are, and if some drugs are more likely to have this effect than others.”

If you have any concerns about the medication you are taking you should see your GP.

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