By Nadia Kounang, CNN
Smoking is the leading cause of preventable death world-wide. About half of all long-term smokers will die because of their addiction. But the good news is that nearly 70% of current smokers want to quit, says the CDC.
And using an effective treatment to help kick the habit can almost double or triple one's chance of success. Replacement therapies like the nicotine patch or gum, or medications like the antidepressant buproprion (sold as Wellbutrin or Zyban) and varenicline (commonly known as Chantix), can help reduce one's cravings to smoke and deal with withdrawal symptoms.
Headlines in recent years have questioned the cardiovascular risks of these drugs. But new research says that these drugs carry little risk of heart attack or stroke.
The new meta-analysis published this week in the journal Circulation is the largest analysis of its kind, with study authors surveying 63 different clinical trials encompassing more than 30,500 smokers. Unlike previous studies, which only looked at the effectiveness and safety of each individual drug, this analysis compared all three methods of smoking cessation.
The study found that none of these three therapies - gum, patch and antidepressants - increased the risk of major cardiovascular events. Those taking Zyban, Wellbutrin and Chantix had lowest risk of any serious heart event, while those taking nicotine replacement therapy, such as gum or a patch, had a slightly increased risk for minor side effects like a rapid or irregular heartbeat.
The study results even suggest that Wellbutrin may even protect against serious cardiovascular events. But the study authors cannot explain why.
"Undoubtedly, the benefits of quitting smoking outweigh any potential risks from smoking cessation therapies," said Dr. Edward Mills, co-author of the study and an associate professor of medicine at the Stanford University School of Medicine.
Mills, along with other study authors, has consulted to Merck, Pfizer, Takeda, Novartis, or GlaxoSmithKline, which all manufacture smoking cessation drugs. However, none of the companies were involved with this particular analysis.
Dr. Jonathan Samet, director of the University of Southern California's Institute for Global Health, argued that a large meta-analysis is difficult and imprecise. "I think they've done technically a good job -- but there's just not as much as we like in terms of the evidence," he said.
He also added, "there isn't a huge risk that we're likely to be missing" when it comes to these therapies.
When looking specifically at the heart, "the main problem are side effects, not heart attack and death," said Dr. Russell Luepker, spokesman for the American Heart Association. "The risks are low, and if you look at the benefits of quitting smoking, they are greater than the benefit."
The findings seem to counter the last meta-anlysis of Chantix back in 2011, which found the drug increased the risk of heart attacks. Mills said that this new study is more precise because of its comparative method, allowing for "greater power and precision" of results.
Wellbutrin, Zyban and Chantix also come with increased mental health risk. In 2009, the US Food and Drug Administration required black box labeling for all three drugs because they cause side effects like behavior changes, depression, hostility, and suicidal thoughts.
However, the FDA also admitted that it was unclear whether some of these effects weren't actually symptoms of nicotine withdrawal .
Mills acknowledged that the risk for suicide and mental health issues remains, "even though all assessments have not demonstrated an effect of these therapies on suicidality. The current thinking is that the stress of quitting may be a causative factor."
What all the doctors do agree on is that quitting smoking doesn't have a blanket prescription, but rather needs to be individualized for the patient. According to Luepker, that most commonly means a combination of both drugs and behavioral therapy, like counseling. "If you can use the two of them, a program plus drug, you're more likely to be successful."
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