Other NSAIDs are available that have lower risks.

A commonly used painkiller diclofenac (contained in the painkiller Difene) is associated with an increased risk of major cardiovascular events, such as heart attack and stroke when compared to similar medicines like paracetamol and ibuprofen, a new study has suggested.

Diclofenac is a traditional non-steroidal anti-inflammatory drug (NSAID) for the treatment of pain and inflammation and is widely used across the world. It only available on prescription here in Ireland and other NSAIDs are available that have lower risks.

For the study, which is published in the BMJ this week, a research team in Denmark, examined the cardiovascular risks of starting diclofenac compared with no NSAIDS, starting other traditional NSAIDs, and starting paracetamol.

The results are based on national registry data of more than 6.3 million adults in Denmark with at least one year of continuous prescription records before study entry in January 1996.

Participants in the study were split into low, moderate, and high baseline cardiovascular risk. The average age was 46-49 years among those who started taking NSAIDs and 56 for those who started paracetamol.

After taking account of potentially influential factors, starting diclofenac during the 20-year study period (1996-2016) was associated with an increased rate of major adverse cardiovascular events within 30 days compared with starting other traditional NSAIDs (ibuprofen or naproxen) or paracetamol.

Events included irregular heart beat or flutter, ischaemic stroke, heart failure, and heart attack. The increased risks applied to men and women of all ages and at low doses of diclofenac.

Starting diclofenac was also associated with an increased rate of cardiac death compared with no NSAIDs, and an increased risk of upper gastrointestinal bleeding compared with no NSAIDs, starting ibuprofen or paracetamol, but not with naproxen.

The authors pointed out that, although the relative risk was increased, the absolute risk remained low for the individual patient.

When results were analysed by baseline cardiovascular risk, the absolute number of events per 1,000 diclofenac starters per year also increased. For example, among patients at low baseline risk, diclofenac starters had one additional event versus ibuprofen starters, one additional event versus naproxen starters, three additional events versus paracetamol starters, and four additional events versus no NSAIDs. Among patients at moderate baseline risk, corresponding figures were seven, seven, eight, and 14 additional events, respectively, and for those at high baseline risk, corresponding numbers were 16, 10, one, and 39 additional events, respectively.

The authors also noted that this was an observational study, and therefore no firm conclusions can be drawn about cause and effect. However, they added that the study’s large sample size provided strong evidence to guide clinical decision making.

According to the authors, “treatment of pain and inflammation with NSAIDs may be worthwhile for some patients to improve quality of life despite potential side effects. Considering its cardiovascular and gastrointestinal risks, however, there is little justification to initiate diclofenac treatment before other traditional NSAIDs.”

They also said it was time to acknowledge potential health risk of diclofenac and reduce its use.

They added that when prescribed diclofenac should be accompanied by an appropriate front package warning about its potential risks.

Commenting on the study Dr Angie Brown, Medical Director of the Irish Heart Foundation said, “Treatment of pain and inflammation with NSAIDs may be necessary for some patients to improve their quality of life despite the potential side effects. However, it is important that these cardiovascular and gastrointestinal risks are discussed, and alternatives sought if possible particularly for those at moderate and high risk of CVD. Furthermore, there is little justification to initiate diclofenac treatment instead of other NSAIDs that have a lower risk.”