19 Dec Smoking Cessation: Less Expensive Cytisine May Be As Effective As Nicotine Replacements
Medical Research: What is the background for this study? What are the main findings?
Dr. Walker: Cytisine is a plant-based alkaloid and is structurally similar to nicotine. It is found in various plants from the Legume Family (Fabaceae), the third largest plant family on earth. Cytisine is currently manufactured by Sopharma Ltd, Bulgaria (Tabex®) and Aflofarm Pharma, Poland (Desmoxan®) as a smoking cessation treatment, with the cytisine used in the tablets taken from a plant called Golden Rain (Laburnum anagyroides). Cytisine has been available with and without prescription for smoking cessation since the 1960s, largely in Eastern Europe. Cytisine is not currently registered for use in any Western countries (although regulatory approval is currently been sought for the USA , UK and Japan).
We know from trial evidence that cytisine is better than a placebo for helping people quit smoking. Cytisine is also one of the most affordable smoking cessation medicines available. It is much cheaper than nicotine patches, gum and/or lozenges and other smoking cessation medicine such as varenicline. This means smokers and governments are more likely to afford cytisine, especially those from low and middle income countries. However, we don’t know if cytisine is as good as nicotine patches and/or gum or lozenges, one of the most commonly used smoking cessation treatments in many western countries. We therefore undertook a pragmatic non-inferiority trial to answer this question, with recruitment of 1310 adult daily smokers who were motivated to quit, undertaken using the New Zealand national Quitline. Smokers were randomised to receive the standard 25 days of cytisine treatment or 8 weeks of nicotine patches and/or gum or lozenges. Both groups received standard Quitline behavioural support. Follow-up occurred at one week and one, two, and six months.
At all time points, cytisine was found to be better at helping people quit smoking than nicotine patches and/or gum or lozenges. This finding was consistent irrespective of ethnicity, age, alcohol consumption, degree of cigarette dependence or whether participants smoked factory-made cigarettes or roll-your-owns. For reasons unknown, cytisine helped more women quit smoking than nicotine patches, gum and/or lozenges. For men the effectiveness of the two products was similar. Cytisine use made people less likely to relapse back to smoking. Those who did smoke when using cytisine didn’t enjoy smoking as much, and reduced the number of cigarettes they smoked. Self-reported, non-medically verified adverse events were more common in those that used cytisine. Three out of every 10 people who used cytisine reported an adverse event, compared to 2 out of every 10 that used nicotine patches, gum and/or lozenges. However the majority of reported side effects were mild and self-limiting. More people in the cytisine group experienced nausea, vomiting and sleep disturbances (e.g. bad dreams).
Medical Research: What should clinicians and patients take away from your report?
Dr. Walker: A ‘one size fits all’ approach should not be taken when considering smoking cessation medications. Smokers should be offered a wide range of effective and safe smoking cessation medications so that they can chose a quitting method than best suits them. Cytisine is another medication that can be added to the ‘mix’ of options for smokers, and may particularly suit those smokers who have tried but failed to quit other treatments, or those who do not wish to use nicotine replacement therapy. The added benefit of cytisine is that it is much more affordable than other smoking cessation medications.
Medical Research: What recommendations do you have for future research as a result of this study?
Dr. Walker: A head-to-head trial comparing the effectiveness of varenicline and cytisine seems the next most obvious step, given the large market price difference between these two medications. Other research is also justified to investigate the current and new dosing regimens, and to undertake long-term safety monitoring.
Cytisine versus Nicotine for Smoking Cessation
Natalie Walker, Ph.D., Colin Howe, Ph.D., Marewa Glover, Ph.D., Hayden McRobbie, M.B., Ch.B., Ph.D., Joanne Barnes, Ph.D., Vili Nosa, Ph.D., Varsha Parag, M.Sc., Bruce Bassett, B.A., and Christopher Bullen, M.B., Ch.B., Ph.D.