The Dementia Action Alliance (DAA), a group of 50 organisations including the RCGP, the Alzheimer's Society and the government, called on GPs to review patients within the next nine months.
RCGP chairwoman Dr Clare Gerada said the reviews would improve patients' lives without significantly increasing GP workload.
In October last year, the DoH announced plans to cut antipsychotic use by two-thirds by November 2011.
The pledge supported the five-year National Dementia Strategy, which aims to improve the quality of care for people with dementia and their carers. As many as four in five of the 180,000 people with dementia on antipsychotics are thought to be prescribed the drugs inappropriately.
This can worsen symptoms of dementia, leave patients unable to walk and increase the risk of stroke and premature death. NICE guidance says antipsychotic use should be a last resort.
Dr Gerada told GP that with 144,000 patients likely being inappropriately prescribed antipsychotics, changes to patient prescriptions would be 'common' but worthwhile.
'This is voluntary but it's good practice. Practices should do a search of drugs prescribed by age group to see if the drug is necessary in each case,' she said.
The DAA has invited GPs and other health professionals to commit to reviewing all patients. Patients and carers will be sent a new information booklet about antipsychotics.
Surrey GP Dr Jill Rasmussen, a GPSI in mental health and learning disability, said GPs must be supported to deliver the changes. 'Providing training and sharing best practice among GPs to increase understanding of managing dementia, especially the use of antipsychotics in behavioural and psychological symptoms, is essential,' she said.
Jeremy Hughes, Chief Executive of Alzheimer’s Society, said: 'It is unacceptable that more than 100,000 people with dementia are having their health and quality of life put at risk because of antipsychotics.’
He added: ‘It’s not just about reducing antipsychotics but also about improving quality care. This means developing alternative treatments and finding better ways to manage pain and other medical conditions.'