Source: http://www.telegraph.co.uk/health/healt ... clots.html
Commonly prescribed drugs to treat nausea and vomiting increase the risk of potentially deadly blood clots by a third, British research has found.
By Rebecca Smith, Medical Editor
Published: 7:30AM BST 22 Sep 2010
Hundreds of thousands of people in England take the new atypical antipsychotics, mainly for schizophrenia, but they are also used to treat common complaints like nausea, vomiting and vertigo.
Researchers said the drugs should be used more cautiously after findings from a study of more than 100,000 people found they were associated with an increased risk of blood clots.
The use of antipsychotics is controversial as evidence that they are effective is limited and charities have warned they are used as a 'chemical cosh' to subdue difficult elderly patients with dementia.
Around 7.2m prescriptions were dispensed for antipsychotics in England last year, including the newer atypical drugs examined in the study.
The team from University of Nottingham investigated around 25,000 people who had suffered a blood clot, either in the legs or in the lung, and compared them with similar people who had not suffered one.
They found around three quarters of the people studied had taken prochlorperazine which is widely used to treat vertigo, nausea and vomiting. It is not effective at treating travel or motion sickness.
The results showed that those prescribed antipsychotics in the previous two years were 32 per cent more likely to have had a blood clot. The more prescriptions a person had received the greater their risk of a clot.
People who had started taking the drugs in the previous three months were at even higher risk of clots, and were twice as likely to have had one than those not on the drugs.
The authors said this meant that there would be four extra blood clots per 10,000 patients treated over one year.
The findings were published online in the British Medical Journal.
Blood clots are a major cause of preventable death and around 25,000 people in hospital die annually from the condition as being immobile in bed increases the risk.
Lead author Professor Julia Hippisley-Cox at the University of Nottingham, wrote: “Though these findings add to the accumulating evidence of adverse health events associated with antipsychotic drugs, they should be confirmed with other data sources.
“If other studies replicate these findings, antipsychotic drugs should be used more cautiously for nausea and agitation etc, especially among patients at high risk of thromboembolism.
“Patients need information on the balance of risks and benefits of these drugs before they start treatment.”
In an accompanying editorial, geriatrics experts Dr Rosa Liperoti and Prof Giovanni Gambassi argue that a higher risk means treatment should be tailored according to individual risk factors.
They said: “Despite their association with serious risks and few data to support their efficacy antipsychotics are widely used, and in 2008 they became the top selling drug class in the United States, ahead of lipid regulators and proton pump inhibitors.
"Despite efforts to improve non-drug based interventions, antipsychotics are often used, especially for the treatment of agitation in people with dementia.
"In clinical practice we need to be able to identify the best candidates for antipsychotic treatment."
