A new study into the anti-smoking drug Champix has renewed concerns about the drug, showing it is associated with an increased risk of heart attack and stroke.
An international study published in the Canadian Medical Association Journal found that people who used it had a 72 per cent higher chance of serious cardiac problems.
About 1.5 million packets of Champix have been dispensed in Australia since its introduction in 2007.
It has not been without controversy, with concerns already raised about the drug's psychiatric side effects.
But after analysing more than a dozen clinical trials, Champix is now being blamed for compounding a smoker's risk of heart attack and stroke.
Dr Sonal Singh from Johns Hopkins School of Medicine in the United States, who co-authored the study, says it is a paradox.
"The paradox is that we take drugs to reduce cardiac risk and what we are seeing is exactly the opposite," he said.
"Among smokers both with and without heart disease we see a substantial increase in serious cardiac risks with Champix - substantial meaning more than 70 per cent.
"All of these have to be taken into consideration with these new psychiatric effects which we are learning more and more about."
And he says the risks persist at least 12 months after the drug treatment ends.
"We don't want people to think that smoking is better - but it becomes harder when the primary purpose of smoking cessation is to reduce cardiac risk and you have the most widely used drug in the world that does just exactly the opposite," he said.
"It's going to be hard to balance, because how am I going to tell my patients that, 'well, you're going to have a short-term risk for a year and then maybe it will decline', because we've never seen studies of Champix going on beyond a year."
Not a new risk
But the cardiac risk may not be entirely related to Champix, according to Renee Bittoun, the head of the Smoking Research Unit at Sydney University's Brain Mind Research Institute.
"I was there in the 1980s when we had nothing to give patients, none of those nicotine products, none of this medication to help smokers quit," she said.
"There were people with increased cardiac events just on the idea that they were going to stop smoking, meaning it made them very nervous, it made them more distressed and that increases your risk of vascular events."
Despite the risks, Professor Garry Jennings from the Baker IDI Heart and Diabetes Institute is standing by the drug.
"Out of the drugs that are used, it's probably the most effective, it probably has double the number of people that are able to stop smoking for a good length of time," he said.
"But that doesn't mean it works in everyone."
But Dr Singh says the Australian drug regulators cannot be confident about the safety of Champix.
"This drug was brought on under the rubric of that this was a new class of drugs that will not have any safety problems and now we know that it has some of the most amount of safety problems of any drug on the market," he said.
"So I think regulators worldwide need to look at how they approve new therapies."
Warnings are already contained in the product information kit for Champix but the Therapeutic Goods Administration says it will review the safety profile of Champix as a result of the new research.
![:\](https://bluelight.org/xf/BL_Images/Orig_Emoji/wrygrin.gif "wry grin :\")
