Risperidone in dementia raises stroke risk, even in ‘low-risk’ patients

Risperidone raises stroke risk without exception in patients with dementia, say researchers who analysed GP records.

A study of 165,000 patients diagnosed with dementia after the age of 65 years between 2004 and 2023 found risk of stroke was increased even in those with no history of heart disease or stroke.

Reporting their findings in the British Journal of Psychiatry they said people with dementia with a prior history of cardiovascular disease are at a significant increased risk of stroke, and risperidone further exacerbates this risk.

But there appears to be no ‘safe group’ because an increased risk was found across all subgroups looked at.

The analysis compared 28 403 risperidone users with 136 324 matched controls.

Risperidone was associated with a 28% increased risk of stroke, the results showed.

This risk appeared substantially higher in those with a prior history of stroke and cardiovascular disease.

 Yet further analysis showed that much of the incidence of stroke is attributable to past medical history rather than risperidone.

The team reported that of the 222 incident strokes during treatment with risperidone in patients with a history of stroke, 177 would have occurred irrespective of whether the drug was taken.

They concluded that ‘clinicians should be mindful of prescribing a drug that increases stroke risk further in an already at-risk group’.

It was the consistency across all groups that was the striking finding explained study author Dr Byron Creese from the College of Health, Medicine and Life Sciences at Brunel University of London.

‘We knew risperidone causes stroke, but we didn’t know whether some groups of people might be more at risk than others.

‘We thought if we might identify characteristics that make people more at risk, doctors could avoid prescribing to patients with those characteristics.’

NHS guidelines limit risperidone use to six weeks for severe symptoms, but many patients take it for longer, with monitoring standards varying across the country, he added.

‘These findings give clearer information about who is most at risk, which helps everyone make more informed choices.

‘Every decision should be based on what is right for each person, through honest conversations between doctors, patients, and families.’

It follows a UK study last year which reported that antipsychotic medication in patients with dementia is linked with a much wider range of serious harms than previously thought.

Although there have been safety warnings on use of the antipsychotics from regulators about increased risk of stroke and death, researchers found increased risks for pneumonia, venous thromboembolism, heart attack, heart failure, fracture, and acute kidney injury.

Reporting the findings in the BMJ, researchers from the University of Manchester said it underscores the need for increased caution when prescribing.