Which everyday drugs have been linked to dementia?

Millions of people are taking routine medication that may significantly increase their risk of developing dementia later in life, scientists are warning.

Research has suggested that anticholinergic medications, prescribed to control muscle contractions or for mental health conditions, may cause mental declines later in life.

The drugs, used by as many as two million people in England alone, “are known to cause short-term confusion, and after previous studies suggested that they might lead to dementia, researchers set out to find stronger evidence”, says The Times.

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The new study, published in the British Medical Journal, looked at the risk of new-onset dementia among almost 325,000 older adults in the UK.

“We found that people who had been diagnosed with dementia were up to 30% more likely to have been prescribed specific classes of anticholinergic medications,” said lead study author Dr George Savva, from the University of East Anglia’s School of Health Sciences.

Antihistamines and other less potent anticholinergics used for travel sickness or stomach cramps were not linked to dementia, the report said.

However, the risk does appear to increase with long-term use of stronger drugs. “The biggest effect was in drugs used for bladder disorders; such as oxybutynin and tolterodine; antidepressants, including amitriptyline and paroxetine; and Parkinson’s disease, including benzatropine and procyclidine,” says The Independent.

Dr Savva and his team say that everyone’s risks will be different, depending on the medicine, their genetic make-up and their lifestyle.

As a general rule, they say, someone with a 10% of developing dementia in the next 15 years would see that increase to 13% if they had been on anticholinergics for a year or more - or a “one in 33 chance of getting dementia you would otherwise not have got”.

Experts emphasise that patients should not stop taking the drugs, as their benefits may outweigh any risk.

Ian Maidment, of Aston University, who co-authored the study, told the BBC: “Don't do anything suddenly. Don’t stop taking your medication.”

The number of older people taking five or more medicines has quadrupled in the past two decades, fuelling the need for more research into the effects of taking a “cocktail” of prescribed drugs, Maidment said.

The focus now should be on “de-prescribing”, he insisted, adding: “Doctors, nurses and pharmacists need to work with older people and their carers to ensure that they take medication only if the benefits clearly outweigh the harms.”

Dr James Prickett, head of research at the Alzheimer’s Society, echoed that advice. He told the BBC that compared with the risk posed by leading an unhealthy lifestyle, the potential risk of an anticholinergic drug contributing to the onset of the disease was “quite small”.