Drug research: The controversial arthritis drug Vioxx, which was withdrawn on safety grounds last year, may have caused up to 140,000 additional cases of serious coronary heart disease in the US, research published today has suggested - the drug was also widely used in Ireland.
Researchers, who include Dr David Graham an assessor with the Office of Drug Safety at the Food and Drug Administration (FDA) examined data from 1.4 million people in California who had taken non steroidal anti-inflammatory drugs (NSAIDS) from 1999 to September 2004.
The study was designed to assess whether the risk of heart attack was increased in people who took Vioxx (rofecoxib) compared to those taking other NSAIDS.
Vioxx was voluntarily withdrawn from the market last September by the pharmaceutical company Merck, Sharp and Dohme, after research linked it to an increased risk of heart disease.
According to the latest study which is published online today by the Lancet medical journal, people taking Vioxx had a 34 per cent higher chance of coronary heart disease compared with people who used other NSAIDS.
However, the study also found a 14 per cent increased risk of heart disease among those taking Naprosyn. It is an established NSAID with a different mode of action to Vioxx, which is an example of a newer group of NSAIDS, called Cox 2 inhibitors. These drugs were marketed as having lesser gastrointestinal side-effects than older arthritis drugs, in particular the risk of haemorrhage.
"In the future, when trials show that a new treatment confers a greater risk of a serious side-effect than a standard treatment, we must be much more careful about allowing its unrestricted use," Dr Graham said.
In separate research published today in the journal Archives of Internal Medicine, researchers from the University of Chicago and Stanford University School of Medicine found evidence that doctors were over-prescribing Cox 2 inhibitors, often in patients at little risk of gastrointestinal side-effects.
"We found a rapid nationwide shift away from older, inexpensive drugs with better established safety and efficacy to newer, costly drugs with no real history," lead author Dr Caleb Alexander said.
However, there was good news for the manufacturers of Cox 2 inhibitors in a separate study also published today.
In a study of 6,250 patients, doctors from the University of Maryland found that Cox 2 inhibitors did not increase the risk of cardiovascular clotting compared with people using established NSAIDS. All patients enrolled in the study were considered to have a high risk of cardiovascular events.
Meanwhile, the Irish Medicines Board has confirmed it has been asked by the European medicines regulatory agency (EMEA) to take the lead in assessing the risks that may be associated with Bextra (valdecoxib) and Dynastat (paracoxib).
The assessment is part of an in depth investigation into the risks of all Cox 2 inhibitors, the results of which are expected next month.