Popular Anti-inflammatory May Increase Risk of Heart Attack, Study Finds

A commonly prescribed painkiller could raise the risk of a heart attack or stroke. The risks are potentially so great that researchers warned that the drug should not be offered over the counter.

Diclofenac is prescribed to treat pain and inflammation, and is marketed under names including Voltaren. The drug is a nonsteroidal anti-inflammatory (NSAID) that can be prescribed by a doctor or sold in a pharmacy in small doses.

Researchers studied data on 6.3 million adults from the Danish National Patient Registry collected in the two decades following 1996. The participants had an average age of between 46 and 49.

To arrive at their findings, published in The BMJ, the team divided participants into categories of low, moderate and high baseline risk of developing cardiovascular disease. All of the participants had been prescribed the painkillers within 90 days of enrolling. The participants were also categorized according to whether they had taken painkillers in the past year, or had regularly used paracetamol and NSAIDs including diclofenac.

Within 30 days of their taking the drug, diclofenac was linked to serious cardiovascular problems such as heart attacks or strokes, while paracetamol and other traditional NSAIDs, such as ibuprofen and naproxen, were not.

A painkiller has been linked with an increased risk of heart attack. Getty Images

However, the authors stressed while there did appear to be an elevated risk, the absolute risk remained low.

The scientists acknowledged that NSAIDs may be necessary for treating pain and inflammation for some patients, despite the potential side effects.

And as the study was observational, meaning it was based on data rather than trials in patients, the researchers couldn't definitively conclude that the drug causes heart problems.

Thoroughly investigating this link by carrying out a large, randomized clinical trial, where patients' painkiller regimes are tampered with, is regarded as unethical.

"Considering its cardiovascular and gastrointestinal risks, however, there is little justification to initiate diclofenac treatment before other traditional NSAIDs," they concluded.

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Novartis, the drug company which manufactures Diclofenac under the name Voltaren, acknowledged that the NSAIDs could heighten the risk of potentially deadly cardiovascular problems. The company did not immediately respond to a request for comment.

"Patients with cardiovascular disease or risk factors for cardiovascular disease may be at great risk," according to a warning posted on the Novartis website. "The increase in CV [cardovascular] thrombotic risk has been observed most consistently at higher doses."

To minimize risk, patients should use the lowest effective dose for the shortest possible duration, Novartis advised.

"Physicians and patients should remain alert for the development of such events, throughout the entire treatment course, even in the absence of previous CV symptoms," said Novartis. "Patients should be informed about the symptoms of serious CV events and the steps to take if they occur."