Vioxx (rofecoxib) was one of a relatively new group of anti-inflammatory medicines known as COX-2 selective inhibitors. It was licensed in the United Kingdom and many other countries for the treatment of arthritic conditions—osteoarthritis and rheumatoid arthritis—and also for the short-term treatment of some painful conditions. COX-2 selective inhibitors are effective anti-inflammatory, pain-relieving medicines that are thought to have less risk of gastrointestinal side effects, for example stomach ulcers, than conventional anti-inflammatory medicines.
Since 2000, evidence from clinical trials had raised concerns about a possible increased risk of heart attacks and other cardiovascular conditions associated with Vioxx, and the Medicines and Healthcare products Regulatory Agency (MHRA)/committee on safety of medicines (CSM) had continually reviewed the cardiovascular safety of this drug since it was first licensed. The product information for healthcare professionals and patients, which lists all the known side effects of the medicine, was updated on a number of occasions on the basis of emerging evidence, and in accordance with CSM's advice.
Data are not available on which to base a valid estimate of the number of heart attacks, strokes and other adverse effects that may have been caused by Vioxx and other COX-2 inhibitors. The underlying medical condition of many patients treated with COX-2 inhibitors means that they are at higher risk of heart attack and stroke than the rest of the population, and the impact of the COX-2 inhibitor on this risk is not possible to calculate.
Since Vioxx was voluntarily withdrawn by the manufacturer in 2004, the safety of other COX-2 inhibitors and traditional anti-inflammatory drugs—non-selective non-steroidal anti-inflammatory drugs (NSAIDs)—has been under continual and intense assessment in the UK and Europe. The latest evidence suggests that both NSAIDs and COX-2 inhibitors might pose a small increased risk of heart attacks or strokes, although the exact level of risk may vary between medicines. Planning is now under way to introduce new information into product information that will support informed decision-making for healthcare professionals and patients in relation to the choice of anti-inflammatory medicine.