BACKGROUND-AIM:
Over 60% of tobacco users want to quit but less than 5% make successful one-year unassisted quit attempts as tobacco use contributes to strong nicotine addiction. Among effective and scientifically proven smoking cessation aids is cytysine. Since 2011, when Professor Zatonski’s team published in New England of Medicine results of the first placebo-controlled clinical trial on the effectiveness and safety of cytisine, millions of Polish smokers have used cytisine for smoking cessation. Then cytisine became widely used not only in CEE countries but also in Western Europe. This paper aims to briefly conclude on the role of cytisine in history of smoking cessation interventions, its pharmacological activity, treatment regimen, safety and clinical and cost-effectiveness.

METHODS:
A brief narrative review of clinical and pharmacoeconomic studies, mainly their systematic and narrative reviews, meta-analyses and randomized clinical trials on cytisine as smoking cessation aid. The search was made in PubMed, Medline, EMBASE, Cochrane Library, Web of Science, Scopus and other research libraries for papers published in peer-review scientific journals in the past 20 years.

RESULTS:
Cytisine is the oldest smoking cessation aid worldwide. It is used in medical practice since over 70 years. Cytisine is plant alkaloid that has a similar chemical structure to nicotine and is a partial nicotine agonist selectively binding to the α4β2 acetylcholine receptors that mediate nicotine dependence. The standard course of treatment for cytisine (1.5 mg tablets) continues 25 days with a quit date at day 5. The course can be repeated to total a 2-month cycle. Some studies show longer treatment with cytisine (from 40 days to 3 months) to be more effective. Clinical studies shows that cytisine mostly contributes to moderate gastrointestinal adverse events and sleep disorders when compared with placebo and NRT. In comparison with varenicline, cytisine produces a fewer adverse effects. The efficacy of cytisine as smoking cessation aid is well-documented in clinical trials. Both for the primary outcome and longer abstinence, cytisine is more efficient than placebo and NRT but does not have so high efficacy as varenicline. When compared with other smoking cessation aids, the cost of a standard 25-day treatment for cytisine is few times cheaper and significantly more cost-effective.

CONCLUSIONS:
Cytisine is the oldest, safe, efficacious, cheap and cost-effective smoking cessation aid as compared with placebo and NRT. It is less clinically effective than varenicline but produces less side effects and is much cheaper and more cost-effective. Although there is still a need for further comparative clinical trials on cytisine, there is enough evidence to recommend cytisine as essential smoking cessation aid in smoking cessation guidelines, use it in routine medical practice and for its global promotion, especially in developing countries and in lower social strata.