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Acetylcholinesterase inhibitors ‘do not slow progression of cognitive impairment’

Treatment of mild cognitive impairment with acetylcholinesterase inhibitors is ‘not associated with any benefit’ and brings an increased risk of side effects, according to a new analysis.

In results experts say raise questions over the Government’s drive for earlier diagnosis of dementia, researchers found ‘cognitive enhancer’ drugs did not significantly slow the progression of cognitive impairment.

The meta-analysis - published in the Canadian Medical Association Journal this month – looked at eight studies using donepezil, rivastigmine, galantamine and memantine in mild cognitive impairment.

They found a non-significant -0.07 mean difference in cognition scores between patients who took donepezil or galantamine, compared with those taking placebo after a mean of 24 week follow-up. They also found after 96 weeks follow-up, those on galantamine had a non-significant mean difference in functional status of 0.30, compared with those taking placebo.

There were also no significant differences seen in mortality rates with acetylcholinesterase inhibitors versus placebo, but there were significantly greater rates of nausea, diahorroea and vomiting, compared with placebo.

The researchers said that their results supported previous analyses of the evidence base for using cognitive enhancers in patients with mild cognitive impairment.

They concluded: ‘Cognitive enhancers did not improve cognition or function among patients with mild cognitive impairment and were associated with a greater risk of gastrointestinal harms. Our findings do not support the use of cognitive enhancers for mild cognitive impairment.’

The introduction of a directed enhanced service this year aiming to reward practices for picking up signs of early dementia in at-risk patients has proved controversial as some experts have claimed it will worry patients unnecessary.

But ministers have vowed to ‘change GPs minds’ over the value of diagnosing dementia earlier, saying that there is a misconception that prescribing medicines earlier will make a difference.

NICE guidelines currently recommend that acetylcholinesterase inhibitors should not be prescribed for early cognitive impairment ‘except as part of properly constructed clinical studies’.

Professor Steve Iliffe, professor of primary care for older people at University College London and a GP in Kilburn, west London, said that the study undermined claims that earlier diagnosis of dementia symptoms was beneficial.

He said: ‘This is yet more evidence that cholinesterase inhibitors and memantine don’t offer beneficial effects in what’s called mild cognitive impairment and that’s very interesting.

‘The drugs have adverse effects. They talk about gastrointestinal ones, which are the common ones, but there are more harms that come around, including falls and syncope and cardiac arrhythmias and an increased risk of needing a pacemaker.

‘It certainly means that you cannot claim that earlier diagnosis is going to be beneficial, because you could start treatment earlier. It’s exactly the opposite-there’s no point in starting treatment earlier because it’s ineffective, so that argument is greatly weakened with this sort of evidence.’


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