study links antipsychotic drugs to clot risk
antipsychotic drugs, especially AstraZeneca's blockbuster Seroquel, may
increase the risk of patients developing life-threatening blood clots, British
researchers said on Wednesday.
from a trawl of tens of thousands of patient records, adds to a growing
body of evidence linking so-called atypical antipsychotics to adverse side
-- which also include Eli Lilly's Zyprexa, Johnson & Johnson's Risperdal
and Bristol-Myers Squibb's Abilify -- dominate the antipsychotic market,
which had sales of $16 billion in 2009, according to Thomson Reuters data.
introduced more than 20 years ago, such drugs cause fewer of the involuntary-movement
problems associated with older medicines but have been linked to diabetes
and increased mortality in people with dementia.
has also been limited evidence linking them with dangerous blood clots,
such as deep vein thrombosis and pulmonary embolism, although previous studies
have been small.
British study, which compared 25,000 cases of patients with venous thromboembolism
(VTE) against 89,000 controls, found people prescribed antipsychotics had
a 32 percent greater risk of serious blood clots, after adjusting for other
potential risk factors.
was greater for people on atypical drugs, rather than older ones, and the
highest risk was seen with Seroquel, which showed a nearly three times increase
on an adjusted basis.
the researchers pointed out that the absolute risks still remained low,
with an excess of four extra cases of VTE per 10,000 patients across all
antipsychotics, and 21 in the case of Seroquel.
these findings add to the accumulating evidence of adverse health events
associated with antipsychotic drugs, they should be confirmed with other
data sources," Julia Hippisley-Cox from Nottingham University and colleagues
wrote in the British Medical Journal.
Liperoti and Giovanni Gambassi of Rome's Universita Cattolica del Sacro
Cuore said in a separate comment that the findings showed the need to identify
the best candidates for antipsychotic treatment and work out those susceptible
to developing side effects.
said it would review the latest study results but the company stood by the
drug's risk-to-benefit profile. A spokeswoman noted that VTE was already
mentioned in the product's label as a rare adverse drug reaction.
agreed last month to pay $198 million to settle some 17,500 U.S. personal
injury claims related to Seroquel, following legal claims about its link
to an increased risk of diabetes.