By Alison Caldwell
Updated Tue Sep 14, 2010 12:20pm AEST
There are calls today for one of Australia’s top-selling painkillers to be banned, after another study linked it to an increased chance of stroke in healthy people.
Commonly sold as Voltaren, diclofenac is available in a number of brands and is as dangerous as the arthritis drug Vioxx, according to the author of the study.
Danish research identified Voltaren, a popular anti-inflammatory analgesic, as one of a class of drugs which increase the risk of stroke.
The eight-year Gentofte University Hospital study examined data from more than 2.5 million Danes who had a prescription for non steroidal anti-inflammatory drugs.
It found diclofenac increased the risk of stroke by 86 per cent in people not previously thought to be at risk.
The study’s author, cardiologist Dr Gunnar Gislason, has said the public needs increased awareness about the cardiovascular risks of these drugs even in healthy people.
In Denmark, diclofenac is only available on prescription but in Australia Voltaren is sold over the counter.
Clinical pharmacologist Professor David Henry is the chief executive of the Toronto-based Institute for Clinical Evaluative Sciences and Adjunct Professor at the University of Newcastle in New South Wales.
He says Voltaren should be withdrawn from sale in Australia.
"The drug has passed its use-by date," he said.
"It is an old drug, it’s turned out to be toxic. There are safer alternatives. There’s no reason to have it on the market, whether it’s prescription or over the counter."
Professor Henry says data from a range of research studies shows the whole class of non-steroidal anti-inflammatory drugs may increase the risk.
"But some drugs are more prone to do it than others and within the group of drugs that are available, the drug which appears to be associated with the most risk that is still on the market is a drug called diclofenac," he said.
"[It has] many trade names, including Voltaren. The drug that has the lowest risk is called Naproxen.
"So those differences in drugs need to be taken into account by people that are in high risk.
"These are people who have risk factors like diabetes, high blood pressure, high cholesterol or have maybe have previously had a heart attack or stroke."
Arthritis drug Vioxx was withdrawn from the market in Australia in 2004 because of an increased risk of heart attack.
A spokeswoman for the Therapeutic Goods Administration (TGA) says it is aware of cardiovascular concerns as a possible side effect of diclofenac and that precautionary statements are contained in the product information.
She says the TGA has received eight reports of heart attacks and one of angina with diclofenac, where a causal association was suspected.
For now though she says the TGA continues to closely monitor these medicines.
Professor David Henry says there is a better way to handle concerns which have been raised in numerous studies.
"This is a situation where you can’t rely on people identifying the adverse effect. It’s not like your skin turns green," he said.
"All these studies have been done, many, many of them in tens of hundreds, thousands of people and they show unambiguously that there’s an increase in risk. So it’s time to act."
The TGA advises the lowest effective dose of diclofenac should only ever be used for the shortest possible duration.