An uncontrolled trial of cytisine (Tabex) for smoking cessation

Objectives: Cytisine (Tabex) has been licensed in Eastern Europe as an aid to smoking cessation for 40 years. Cytisine is a partial agonist with high affinity binding to the alpha 4 beta 2 nicotinic acetylcholine receptor believed to be central to the rewarding effect of nicotine. There is insufficient information on effectiveness to warrant licensing by modern standards. To assess whether full-scale controlled trials are warranted, this study sought to obtain an estimate of the 12-month continuous abstinence rates of smokers using cytisine with minimal behavioural support. Design: An uncontrolled, open-label trial. Setting: A smokers' clinic in an oncology centre in Warsaw, Poland. Subjects: 436 consecutive attendees of the smokers' clinic of whom 191 were male. The mean dependence score (Fagerstrom Test for Nicotine Dependence) was 6.1. Intervention: The standard regimen of Tabex (cytisine) was used, involving 25 days of treatment with minimal behavioural support. Main outcome measure: Self-reported continuous abstinence for 12 months; with abstinence verified by carbon monoxide at the final follow up (after 12 months). Results: 60 participants (13.8% of the total sample) were abstinent for 12 months. Of the 315 subjects, who had taken the drug, 49 (15.5%) stopped cytisine because of adverse effects (mostly gastric disturbances and nausea), although they were not serious. The frequency of the minor adverse effects, primarily gastric disturbance, was similar to that observed in previous studies with the drug. Conclusions: The long-term abstinence rates were similar to those observed in smokers receiving nicotine replacement therapy. Full-scale randomised trials of cytisine (Tabex), conducted to the standards required by regulatory authorities, are warranted.