Publishing today in the Canadian Medical Association Journal (CMAJ), the researchers investigated the cardiovascular effects of Varenicline – a smoking cessation drug with more than 70,000 prescriptions each month in the UK. Varenicline is recommended by the National Institute of Clinical Excellence (NICE) to help smokers who are planning to give up smoking.
“We analysed 14 clinical trials involving more than 8200 otherwise healthy smokers and the likelihood of developing serious cardiovascular events resulting in hospitalisation, disability or death was almost 72 per cent higher in patients using Varenicline,” said joint lead author Dr Yoon Loke of Norwich Medical School at UEA.
Varenicline is used by heavy smokers who find it difficult to quit the habit and is recommended by NICE. The presciption-only drug reduces both the craving for and pleasurable effects of cigarettes. It is one of the most widely used drugs for smoking cessation – despite the US Food and Drug Administration (FDA) already warning that it can cause depression and suicidal thoughts.
The systematic review and meta-analysis used data from 14 double-blind randomized controlled trials lasting between one and 52 weeks. While the number of serious heart problems was low at around 1 per cent, Dr Loke cautioned that most of the studies were carried out in healthy people.
“Though the actual numbers of patients developing heart problems on Varenicline is relatively low, these are life-threatening diseases and so any increased risk should be carefully avoided – particularly as heavy smokers are already susceptible to cardiovascular disease,” he said. “In smokers who have a history of heart disease, we estimate that 1 in 28 of them would be troubled by additional heart problems if they used this drug for a year.”
“Long-term trials are now needed to determine whether or not the overall health benefits of this drug outweigh the risks. In the meantime, I would advise people taking Varenicline not to stop taking their medication suddenly, but to discuss any concerns with their doctor – particularly if they already have any heart-related health problems.”
Dr Loke added that his research team recognised the considerable health benefits of giving up smoking and emphasised that were many other drug and non-drug choices for smokers who needed help in quitting.
‘Risk of serious adverse cardiovascular events associated with Varenicline: A systematic review and meta-analysis of randomized controlled trials’ by S Singh (Johns Hopkins University), Y Loke (UEA), J Spangler (Wake Forest University) and C Furberg (Wake Forest University) is published on July 4 2011 by the CMAJ.