The use of antipsychotics to control dementia patients has come under fire again, with a retrospective cohort study from Canada and the US finding that older adults given the drugs were more than three times as likely to experience a serious adverse event leading to hospitalisation or death within 30 days of initiating treatment.

In the population-based study published in the Archives of Internal Medicine (2008; 168(10): pp. 1,090-1,096), researchers led by Dr Paula Rochon from the Departments of Medicine and of Health Policy, Management and Evaluation at the University of Toronto examined the effects of antipsychotic therapy – both atypical and conventional – in 20,682 matched older adults with dementia living in the community and 20,559 matched individuals living in nursing homes between 1 April 1997 and 31 March 2004.

While cohort studies evaluating the safety of antipsychotic therapy generally focus on a single adverse event, Rochon et al looked at the chances of developing any serious adverse event – a composite outcome defined as an event serious enough to lead to an acute care hospital admission or death within 30 days of starting antipsychotic treatment – to give a better picture of the overall burden of short-term harm associated with these drugs.

The analysis revealed that, compared with those not given antipsychotics, community-dwelling older adults newly dispensed an atypical antipsychotic were 3.2 times more likely (95% confidence interval (CI): 2.77-3.68) to experience any serious event during the 30 days of follow-up. Community-dwelling older adults who received conventional antipsychotic therapy were 3.8 times more likely (95% CI: 3.31-4.39) to develop a serious event within 30 days.

The pattern of serious events was similar but less pronounced among older adults living in nursing homes, the authors noted. Within this cohort, residents given atypical and conventional antipsychotics respectively were 1.9 times and 2.4 times more likely to experience a serious event within 30 days of starting treatment.

According to the researchers, around 17% of people going into nursing homes are given antipsychotics within 100 days of admission. “Antipsychotic drugs should be used with caution even when short-term therapy is being prescribed,” they concluded.

A recent report by the All Party Parliamentary Group on Dementia and the Alzheimer’s Society called for a halt to the “dangerous overprescribing” of antipsychotics, saying they were used inappropriately to treat as many as 105,000 dementia patients in the UK.

In April 2005, the US Food and Drug Administration asked manufacturers to add a boxed warning to the labelling of atypical antipsychotics to highlight an increased risk of death among elderly patients prescribed the drugs for the off-label treatment of dementia.