A powerful anticoagulant’s record is being reviewed by the authorities after several studies questioned its effectiveness in some patients.
The Food and Drug Administration has asked Bristol Myers Squibb – the company which produces Plavix – to cooperate in conducting further studies to better understand the effects of genetic factors and other drugs, in particular the proton pump inhibitors (PPIs) commonly taken for heartburn, on the effectiveness of Plavix.
Cardiologist Dr Richard N. Fogoros writes in his Heart Disease Blog that studies have shown that patients with either of two particular risk factors who take Plavix appear to have a significantly higher risk of coronary artery thrombosis than those without the risk factors.
The factors include a genetic variant, which is fairly common in the American population, and the the use of PPIs to reduce stomach acid. The presence of either appears to reduce the effectiveness of the drug which may have fatal consequences in patients at risk of blood clots.
This is not the first time anti-coagulants face scrutiny. Late last year, scientists established a link between the use of wafarin and increased incidence of intracranial bleeding, in particular if combined with some common over-the-counter medications.