The decision not to make available a series of dementia drugs to Alzheimer's sufferers is "a kick in the teeth for millions of people", a charity said today.

Health professionals and charities are considering asking for a judicial review of what they claim is a flawed ruling by the National Institute for Health and Clinical Excellence (Nice).

The treatments watchdog today rejected an appeal against guidance that the drugs should only be used for people with moderate Alzheimer's.

Neil Hunt, chief executive of the Alzheimer's Society, said: "We are extremely unhappy and we are very angry at what we see as a kick in the teeth for millions of people."

Mr Hunt said the appeals process had "overlooked an enormous amount of evidence" and was "victimisation of the most vulnerable in society".

Help the Aged said it was "botched policy-making at its worst".

Doctors fear they will be left in the "unethical" position of having to turn away patients with the early stages of the disease.

Thanks to their treatment, many have been able to return to normal lives despite having reached the stage where they could not recognise close relatives.

The Alzheimer's Society says that 750,000 people in Britain suffer from dementia, 57% of them from Alzheimer's, while hundreds of thousands more are involved in their day-to-day care.

By 2010, the figure for dementia sufferers is expected to rise to 840,000 and by 2050 to 1.5 million. Experts believe it is under-diagnosed.

Sufferers with early or late-stage Alzheimer's will now be denied three drugs: Aricept (donepezil), Reminyl (galantamine) and Exelon (rivastigmine).

Another drug, Ebixa (memantine) is only to be used in clinical studies for people with moderately severe to severe Alzheimer's.

The guidance, which Nice will formally recommend to the NHS in November, is expected to affect 50,000 people a year with early stages of the illness.

Keith Turner, a 68-year-old great grandfather from Hastings, East Sussex, described how his life had been transformed when he started using Aricept two years ago.

Mr Turner and others like him who are already using the drugs will be allowed to continue, but newly-diagnosed patients will not be prescribed them.

He said: "This is a very bleak day."

From being prone to becoming lost, not recognising his wife, and unable to watch the television or read, he is now able to drive a car, go shopping, and work at his local branch of the Alzheimer's Society.

"This tablet, £2.50 a day which they say I'm not worth, my goodness, I reckon it's better than winning the lottery," he said.

"I have got my life back. Why should Nice, who have never been down that path, deny people like myself the opportunity?"

He claimed that neither his offer to give evidence to Nice as a testimony to the effectiveness of the drug, nor to meet Health Secretary Patricia Hewitt, had been taken up.

Professor Roy Jones, director of the Research Institute for the Care of Elderly at St Martin's Hospital, Bath, said: "I am going to be put in the unethical and difficult position of saying, 'I'm sorry, you must come back when you are worse'."

Prof Jones claimed Nice's formula for its analysis was flawed and inappropriate.

He added: "The cost-effectiveness people have over-ridden the people who give care on a daily basis and the people with dementia."

Peter Laycock, a psychiatric nurse and trustee of the Alzheimer's Society, said the drugs enabled people to plan for the future.

He said: "If you can give people that chance so that they can do all the things they wanted to do, put their affairs in order and spend quality time with their families, why are people being denied this?"

Andrew Chidgey, head of policy at the Society, said legal action was being considered, saying: "It is tremendously expensive, but if we don't get any further we will have to give that consideration."

Drug manufacturers were also considering asking for a judicial review.

Dr David Anderson, chairman of the Faculty of Old Age Psychiatry at the Royal College of Psychiatry, said he was "astonished" at the " short-sighted" decision based on a "deeply flawed process".

"Implementation of this guidance will set the treatment of Alzheimer's disease back 10 years," he said.

Jonathan Ellis, senior policy manager at Help the Aged said: "On the one hand, the Government says it is committed to improving care for older people, while on the other Nice is blocking access to treatment which would help them retain their independence and dignity. This is botched policy-making at its worst."

A number of other health experts backed Nice's decision, but others said the health economic analysis used to reach it was unreliable.

Today's decision by Nice could see patients having to buy treatments themselves, often costing much more than the £2.50 a day it costs the NHS.

Campaigners said Nice's decision would leave sedatives as the only treatment for many, which increased the risk of heart attack and stroke.

Nice chief executive Andrew Dillon said: "Alzheimer's is a cruel and devastating illness and we realise that today's announcement will be disappointing to people with Alzheimer's and those who treat and care for them.

"But we have to be honest and say that, based on all the evidence, including data presented by the drug companies themselves, our experts have concluded that these drugs do not make enough of a difference for us to recommend their use for treating all stages of Alzheimer's disease.

"We have recommended the use of these drugs where they have the potential to make a real difference, which is at the moderate stage of the illness."

A Department of Health spokeswoman said it would be "entirely inappropriate" to step in and overrule Nice's decision.