AN INCREASED risk of stroke and heart attack caused by the anti-inflammatory medication Vioxx continued for one year after patients stopped taking the drug, research published today has found.
Rofecoxib (Vioxx) was withdrawn from the market in September 2004 after a major trial found that taking the non-steroidal anti-inflammatory drug (NSAID) for three years was associated with a doubling of the risk of cardiovascular side effects.
As a result, the cardiovascular safety of other coxibs came under intense scrutiny.
The authors of the original research, which was carried out to see if Vioxx could help prevent cancer of the colon, have now followed up the 2,500 patients who were enrolled in the study to see if the risk of stroke, heart attack and premature death persisted.
The results, published online by The Lancetthis morning, show that the risk of heart attack or stroke was doubled in the year after the trial ended, while the risk of death increased by 31 per cent.
Prof John Baron of the Department of Medicine, Dartmouth Medical School, New Hampshire and his co-authors said: "Our data are compatible with an early increase in risk that seems to persist for about one year after three years of treatment. The cardiovascular toxicity seems to be a class effect; indeed studies of other selective Cox-2 inhibitors have reported similar findings.
"All these drugs are effective analgesic and anti-inflammatory agents, and seem to reduce risks of colorectal neoplasia [cancer].
"However, these benefits will have to be weighed against their possible cardiovascular risks in assessing their suitability in various clinical settings."
The results are especially relevant to people with osteoarthritis and other painful musculoskeletal conditions. They suggest that even for patients with no known risks for cardiac disease or stroke, the prolonged use of NSAIDs increases the risk of a cardiovascular event.
Experts have pointed to the fluid retention and blood-pressure raising effects of coxibs as possible reasons for these cardiovascular problems.
By inhibiting a key enzyme, the drugs may also destabilise blockages in coronary and other arteries.
Commenting on today's research, Dr Brian Maurer, medical director of the Irish Heart Foundation (IHF), said "it reaffirms the caution with which we approached these issues in the last few years".
"There needs to be a strong indication in terms of symptom relief to warrant using these drugs in certain people."
In an editorial accompanying the research, Dr Colin Baigent of the University of Oxford and Dr Carlo Patrano of the Catholic University of Rome said: "The results of randomised trials are consistent with all coxibs having some vascular risk, but also with some older NSAIDs carrying similar risks."
They warn that switching a patient from a coxib to a traditional NSAID may not reduce these cardiovascular hazards but will result in a two to three-fold increase in the risk of a serious gastrointestinal complication such as bleeding.