Background and review questions
Some medications and supplements that have been used to treat depression (antidepressants) have been tested to see whether they also help people who are trying to stop smoking. Two antidepressants, bupropion (Zyban) and nortriptyline, are sometimes prescribed to help with quitting smoking. This review set out to determine if using antidepressants increased people's likelihood of successfully quitting smoking at six months or longer and to determine the safety of using these medications to help quit smoking.
The evidence is current to July 2013. This update includes 24 new studies, and this review includes 90 studies overall. The studies included people who smoked and people who had recently quit smoking. There were 65 trials of bupropion, which is licensed for use as a smoking cessation medication under the trade name 'Zyban'. There were ten trials of nortriptyline which is a tricyclic antidepressant which is not licensed specifically for smoking cessation. We only included studies which measured long term quitting (whether or not people had quit smoking at six months or longer from the start of the study).
Key results and quality of evidence
Trials of bupropion (Zyban) for smoking cessation show high quality evidence that it increases the likelihood of a quit attempt being successful after at least six months (44 trials, over 13,000 participants). The side effects of bupropion include insomnia, dry mouth and nausea and rarely (1:1000) seizures and perhaps psychiatric problems, but the last is unclear. There is also moderate quality evidence, limited by a relatively small number of included studies and participants, that the antidepressant nortriptyline increases quit rates (six trials, 975 participants). The side effects of this medication include dry mouth, constipation, nausea, and sedation, and it can be dangerous in overdose. Selective serotonin reuptake inhibitor antidepressants (for example, fluoxetine), monoamine oxidase inhibitor antidepressants (for example, selegiline), and the antidepressant venlaxafine have not been shown to help smoking cessation, nor has the herbal therapy St John's wort, or S-Adenosyl-L-Methionine (SAMe), a dietary supplement that is thought to have antidepressant properties.
Discussion and considerations
The way in which bupropion and nortriptyline might work is not fully understood. Both appear to help people quit smoking whether or not they have a history of depression, or have depressive symptoms when they stop smoking. The likelihood of quitting using bupropion or nortriptyline appears to be similar to that for nicotine replacement therapy, but the likelihood of quitting using bupropion appears to be lower than the likelihood of quitting using varenicline.