Researchers in the UK have found that all drugs used in psychosis treatment are associated with an increased risk of stroke. The findings are published on bmj.com, and include evidence that people who both suffer from dementia and use antipsychotics are at double the risk of stroke compared to those without dementia.
Earlier studies have shown that patients who take second generation (atypical) antipsychotic drugs are at an increased risk of stroke, but there is little research on how first generation (typical) antipsychotics affects stroke risk or on how risk differs people with and without dementia. In 2002 physicians began raising concern regarding the potential increase in stroke risk for patients taking atypical antipsychotic drugs – especially in people with dementia. In fact, a recommendation from the UK’s Committee on Safety and Medicines came in 2004 that said atypical antipsychotics should not be used in people with dementia, even though there was still no clear evidence to support the suggestion.
To further explore the relationship between stroke and antipsychotics, a team of researchers led by Ian J Douglas (London School of Hygiene and Tropical Medicine) analyzed data from the General Practice Research Database (GPRD). The GPRD consists of clinical information on more than six million patients in the UK registered at over 400 general practices. The researchers analyzed a subsample that included 6.790 patients who had a recorded incident of stroke and at least one prescription for any antispychotic medication between January 1988 and the end of 2002.
The researchers found that while patients were receiving any antipsychotic drug, they were 1.7 times more likely to have a stroke compared to while not taking an antipsychotic. This effect nearly doubled to 3.5 times more likely for people with dementia. In addition, people taking atypical antipsychotics have a slightly higher probability of having a stroke compared to those taking typical antipsychotics. No analysis was completed to understand the specific mechanisms that are behind these differences.
“We have established that all types of antipsychotics carry an increased risk, although the risk might be somewhat higher with the atypical drugs,” write the authors. “We reaffirm that the risks associated with antipsychotic use in patients with dementia generally outweigh the potential benefits, and in this patient group, use of antipsychotic drugs should be avoided wherever possible,” they conclude.
Exposure to antipsychotics and risk of stroke: self controlled case series study
Ian J Douglas and Liam Smeeth
BMJ (2008). 337: a1227.
doi:10.1136/bmj.a1227
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Written by: Peter M Crosta