Confirmation that drugs such as ibuprofen, which the Cox-2 inhibitors were designed to replace, also carry an increased risk of heart attack puts the risks of Vioxx in a different light.

The drug is one of the most widely used remedies for headaches, menstrual pain and discomfort caused by inflammation. It is used daily by millions of arthritis sufferers.

But researchers found there was no danger for occasional users, and its benefits for patients who depend on it to lead normal lives were still likely to outweigh its risks.

Findings Shed New Light on Vioxx

The study is the largest and most definitive of its kind into the effect of non-steroidal anti-inflammatory drugs (NSAIDs) on the heart, involving 138 trials covering 140,000 patients.

There is concern over a separate group of anti-inflammatories -- known as the Cox-2 inhibitors -- which led to the withdrawal of Vioxx in 2004 after it was linked with an increased rate of heart attacks. Vioxx, made by Merck, is the subject of a series of multimillion-dollar lawsuits from patients who suffered heart attacks they claim it caused.

Now confirmation that drugs such as ibuprofen, which the Cox-2 inhibitors were designed to replace, also carry an increased risk of heart attack puts the risks of Vioxx in a different light.

The Cox-2 inhibitors, known as Coxibs, have fewer side-effects on the gut than NSAIDs such as ibuprofen, which can cause gastrointestinal bleeding. Some researchers question whether Vioxx should have been withdrawn.

Three Extra Heart Attacks per 1,000

Scientists from the clinical trial service unit at Oxford University, with colleagues from the University of Rome, conducted the study, published in the British Medical Journal.

They combined results of all trials of the two classes of drug to provide the most reliable estimate of risk. Two NSAIDs drugs, ibuprofen and the prescription-only diclofenac, increased the risk of a heart attack by almost as much as the Coxib drugs, but a third drug, naproxen, did not.

The researchers say most patients in the trials did not have heart disease and the increased risk was modest, amounting to three extra heart attacks in every 1,000 people taking ibuprofen or diclofenac every year.