"Diclofenac poses a cardiovascular health risk compared with non-use, paracetamol use and use of other traditional non-steroidal anti-inflammatory drugs", the cardiologist said.
Now a groundbreaking study of more than six million people, the biggest of its kind, has linked them to "major cardiovascular events". According to Daily Mail, many parts of the world - including the United Kingdom - have banned diclofenac as an over-the-counter medication because of its adverse effects on the cardiovascular system.
However, its cardiovascular risks compared with those of other traditional NSAIDs have never been examined in large randomised controlled trials, researchers said.
Using national population and prescription drug registries, they were able to look at the medical records of over 6 million Danish adults from 1996 to 2016.
Reporting on their study in thebmj, the Aarhus University Hospital researchers say diclofenac shouldn't be available over-the-counter, and should only be prescribed with boxfront warnings.
While NSAIDs are commonly recommended to treat inflammatory conditions, headaches, and fever, the drugs are thought to have some cardiovascular risks.
The researchers said that given the risks, doctors should be initiating treatment where indicated with other types of NSAIDs before considering diclofenac.
Diclofenac initiators were also at 20% increased risk compared to patients taking ibuprofen or paracetamol, and at 30% increased risk compared to those taking naproxen.
The risk of gastrointestinal bleeding at 30 days increased 4.5-fold in patients who started diclofenac compared to those who didn't. These risks applied to both men and women of all ages and even at low doses of diclofenac.
Also, it's important to note that this is an observational study, so no cause-effect relationship was established.
"Treatment of pain and inflammation with NSAIDs may be worthwhile for some patients to improve quality of life despite potential side effects", they write. However, the study's sample size is larger than most previous analyzes of observational and randomized studies taken together and provides strong evidence to guide clinical decision making. The problems included cardiac arrhythmia, heart failure, ischemic stroke, stroke, premature death of cardiovascular disease and gastrointestinal haemorrhage.