Smoking Cessation Drug Side Effects Aren't as Bad as You Think

Christopher Labos, MD, CM, MSc


May 17, 2022

I was recently told that May 31 is World No Tobacco Day. Of course, in my world, every day is no tobacco day and the best day to quit smoking is today. Quitting smoking is obviously hard and most people have to try (and fail) multiple times before they break the habit for good. There's a reason Mark Twain supposedly said, "Quitting smoking is easy: I've done it thousands of times."

Telling someone to quit cold turkey is not the best strategy. There are a number of treatment options out there and we should be using them more than we currently do. 

Nicotine Replacement Therapy

The mainstay of anti-smoking medical treatment is and probably will continue to be nicotine replacement therapy (NRT). NRT has a number of advantages, including a long track record of use, low price, and ease of access because in most places it is available without a prescription. But some people may still be concerned about the risks of nicotine replacement, especially in patients with a history of cardiac disease. The concern is based on the theoretical worry that nicotine is a stimulant and vasoconstrictor that can raise blood pressure and increase cardiac demand. But smoking is so bad for you that even a small risk associated with NRT would probably be outweighed by the benefits of quitting the habit.

Even so, concerns about the safety of NRT persist and it is a question that keeps coming up despite the data suggesting that such concerns are unfounded. The EAGLES study proved, I think rather clearly, that there is no major cardiovascular risk to starting anti-smoking medications. This study looked not just at NRT but also at varenicline and bupropion for good measure and found no safety signals with any of them. But the cardiovascular safety of NRT seems to be a niggling doubt that most people can't shake. Even in the arguably more high-risk situation of patients admitted with acute coronary syndromes, NRT doesn't seem to be associated with an increased risk.


Varenicline also has a bit of a reputation. Its safety is also attested to by the EAGLES trial, but it can't seem to shake the reputation of possible psychiatric side effects seen in the initial postmarketing period. Even the removal of the black box warning by the FDA hasn't really changed that perception. A 2015 meta-analysis in The BMJ also found that varenicline was overall safe with no signal of increased suicidality, depression, irritability, aggression, or death. It was, however, associated with an increase in the risk for sleep disturbance, insomnia, and abnormal dreams. While none of this is life threatening, I've had patients who were freaked out by these side effects and not keen to retry the drug.

Varenicline slightly outperformed the other options in a head-to-head analysis of the EAGLES data and in some but not all additional studies. But we need to remember that the goal is to get patients to quit smoking, and whatever achieves that should be considered a success. If people have a hard time quitting, I am inclined to try any and all of these medications.

NRT combo therapy, meaning gum plus patch, outperforms either therapy alone. Telling patients about proper technique with nicotine gum also helps because you need to "chew and park" the gum to get optimal results.

Some studies suggest a benefit to combining NRT with varenicline but at the expense of more side effects.

I find it hard to recommend one product over another unless the patient has specific considerations or contraindications. The best strategy is simply to start something. Many physicians are reluctant to prescribe pharmacotherapy for smoking cessation. Whether the issue is time constraints, worries about side effects, or unfamiliarity with some of the newer medications is unclear. None are good excuses for not doing something.

Helping someone quit smoking is probably the best thing that you can do to make them healthier. Isn't that the whole point of being a physician?

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About Dr Christopher Labos
Christopher Labos is a cardiologist with a degree in epidemiology. He spends most of his time doing things that he doesn't get paid for, like research, teaching, and podcasting. Occasionally he finds time to practice cardiology to pay the rent. He realizes that half of his research findings will be disproved in 5 years; he just doesn't know which half. He is a regular contributor to the Montreal Gazette, CJAD radio, and CTV television in Montreal and is host of the award-winning podcast The Body of Evidence.


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