Doctors are being urged to cut back on prescribing antipsychotics to dementia patients after the largest study of its kind found they are linked to more harmful side effects than previously thought.
The powerful drugs are widely prescribed for behavioral and psychological symptoms of dementia, such as apathy, depression, aggression, anxiety, irritability, delirium and psychosis. Tens of thousands of dementia patients in England are prescribed them every year.
Concerns about the drugs’ safety have been raised before, with warnings to doctors based on increased risks of stroke and death, but evidence of other dangers has been less convincing.
New research suggests there is a significantly wider range of harms associated with its use than previously recognized in regulator warnings, underscoring the need for greater caution in the early stages of treatment.
The use of antipsychotic medications in dementia patients was associated with increased risks of a wide range of serious side effects, including stroke, blood clots, heart attack, heart failure, fractures, pneumonia and acute kidney injury, the study authors reported. Their findings were published in the BMJ.
Charles Marshall, professor of clinical neurology at Queen Mary University of London, who was not involved in the study, said: “This evidence should prompt renewed efforts to reduce the prescribing of antipsychotics to people with dementia.
“There are rare circumstances where antipsychotics are truly necessary and the benefits outweigh these risks, but for the majority of patients with behavioral symptoms that could lead to them being prescribed antipsychotics, we should focus on much safer behavioral management approaches.”
The study examined data from 174,000 adults registered with GP practices in England between 1998 and 2018 and diagnosed with dementia.
During the study, 35,339 people were prescribed antipsychotics – 63% of whom were women – and their medical records were compared with those of dementia patients who were not prescribed these drugs.
Academics from the Universities of Manchester, Nottingham, Edinburgh and Dundee found that dementia patients who took antipsychotics had a twofold increased risk of developing pneumonia compared to those who did not.
Researchers also found that dementia patients taking antipsychotics had a 61% increased risk of stroke and a 43% increased risk of breaking a bone. There was also a 28% increased risk of heart attack and 27% increased risk of heart failure.
Patients with dementia who were prescribed antipsychotic medications appeared to have a 72% increased risk of kidney damage and a 62% increased risk of developing a type of blood clot called venous thromboembolism. The increased risks appeared highest in the first week after treatment.
The study was observational, so no firm conclusions could be drawn about cause and effect. But the authors wrote: “The range of adverse effects was wider than previously highlighted in regulator warnings, with the highest risks occurring shortly after starting treatment.”
Prof Darren Ashcroft, senior author of the study, from the University of Manchester, said: “In recent years it has become clear that more and more people with dementia are being prescribed antipsychotics, despite existing safety warnings in the regulations.
“It is important that any potential benefits of antipsychotic treatment are carefully weighed against the risk of serious harm, and treatment plans should be reviewed regularly in all health and care settings.”
Commenting on the study, Dr Sheona Scales, research director at the charity Alzheimer’s Research UK, said the findings suggested the risks may be more serious than previously thought, which was “particularly worrying given the increase in their use during the pandemic ”.
Dr. Tom Russ, an honorary consultant psychiatrist at the University of Edinburgh, added: “This study does not suggest to me that these drugs should never be used, but that they should be used sparingly in situations where other options have been explored.”