A postcode lottery is denying key drugs to Alzheimer's patients in some parts of the country, according to data published by IMS Health and published in GP newspaper.
The drugs include cholinesterase inhibitors such as donepezil, rivastigmine and galantamine, which are only approved for people with moderately severe Alzheimer's disease.
The 2007 decision by the National Institute for Health and Clinical Excellence (NICE) to limit availability led to protests by campaigners.
The data now show that the drugs are used least in the South West and West Midlands, and most in the North West and South Central regions. Regional variations are as much as 70%.
Overall use of the drugs in the UK has increased by a third from the year ending September 2006 to the year ending September 2008.
However, Professor Clive Ballard, director of research at the Alzheimer's Society, says use of anti-psychotic drugs is "inappropriately high", and they should only be considered for severe symptoms or for short periods in exceptional circumstances.
Meanwhile, says a spokesman for the Department of Health adds: "Our review into the use of anti-psychotic drugs for dementia will be completed shortly."