Cytisine Compared to Combination NRT in Relapsed Smokers

Cigarette smoking is a causative factor in the development of coronary heart disease (CHD), and is the most dangerous form of tobacco use. Effective treatments for smoking cessation exist but relapse to cigarette smoking is common, principally due to nicotine addiction and related symptoms of withdrawal. Little is known about how best to support smokers who have relapsed in subsequent attempts to change their smoking behavior. One emerging treatment has features that might make it appealing to smokers and may be effective in the setting of recent relapse: cytisine. Cytisine is a plant-based smoking cessation medication with more than 50 years of use in central/eastern Europe. Cytisine is a partial agonist of nicotinic acetylcholine receptors (nAChRs), which is central to the effect of nicotine on the reward pathway. Cytisine acts by reducing the rewarding effect of nicotine and attenuating nicotine withdrawal symptoms. A recent review concluded that cytisine is the most promising future smoking cessation treatment. Cytisine is inexpensive to produce and is currently priced much lower than other cessation medications. It is well-tolerated by smokers and requires a shorter treatment period (i.e. 25 days) than conventional treatments. Because it is plant-based, cytisine may be attractive for smokers who prefer 'natural' medicines. Numerous placebo-controlled studies have demonstrated the safety and efficacy of cytisine. One high-quality pragmatic non-inferiority trial (n = 1310) found that cytisine was superior to nicotine replacement therapy (NRT) in improving self-reported continuous abstinence rates at 1 week, and 1, 2 and 6 months when both groups received minimal behavioural support. In Canada, cytisine is marketed as the natural health product Cravv™. The long-term goal is to conduct a definitive, large-scale randomized controlled trial (RCT) of the efficacy of cytisine compared to conventional treatment (i.e. combination NRT) for smoking cessation among smokers who have relapsed to smoking following hospitalization for a CHD-related event. Prior to conducting a larger, definitive RCT there is a need to conduct a pilot study to better understand the potential feasibility of such a trial.