A common European tree could help people around the world kick their smoking habit (Image: Steffen Hauser/Getty)

If quitting smoking is one of your New Year’s resolutions, we might have just the thing. Cytisine, a plant extract commonly used in eastern Europe to wean people off cigarettes, appears to be much better at the task than nicotine replacement patches and gums.

Not to be confused with the DNA building block cytosine, cytisine is an alkaloid extract from the laburnum or golden rain tree (Laburnum anagyroides), which grows all over Europe. It works by blocking nicotine’s access to the brain’s pleasure receptors.

Like nicotine, cytisine is toxic when ingested in large amounts but is safe at low doses. It is produced commercially mainly in Bulgaria and Poland, and has been used as a quitting aid in eastern European countries since the 1960s but is largely unknown elsewhere. Clinical trials carried out in the 60s and 70s did not meet US and European standards so did not lead to wider adoption.


Another look

Researchers in New Zealand have now carried out a fresh trial of cytisine. They recruited 1310 smokers who intended to quit and gave exactly half of them cytisine as a course of tablets, taken daily in diminishing doses for 25 days. The other half received standard nicotine replacement therapy (NRT) – either as patches, gums or lozenges – for two months.

The researchers noted the number of people who managed to abstain from smoking at one week, one month, two months and six months into the trial. Throughout, they found that people taking cytisine were less likely to have smoked than those using NRT. Six months in, 143 of the 655 cytisine recipients were still not smoking compared with 100 in the NRT group.

People who received cytisine were slightly more likely to experience side effects, including nausea, vomiting and sleep disturbance, but these were never serious. “Of those people in the cytisine group experiencing a side effect, the majority said they’d still recommend cytisine to someone who wanted to stop smoking,” says study leader Natalie Walker of the University of Auckland’s National Institute for Health Innovation.

Major appeal

Crucially, Walker says, cytisine is more affordable than other quitting aids. For example, it costs just $20 to $30 for a 25-day course of treatment, versus $100 to $700 for a two-month course of NRT depending on the product and who supplies it, or around $500 for a three-month course of varenicline (Champix), a drug that works in a similar way to cytisine. “Smokers and governments in most low and middle-income countries can’t afford NRT, so cytisine will definitely have a major appeal to them,” she says.

Robert West of University College London, who studies tobacco quitting patterns, is also enthusiastic about cytisine’s potential. In 2011, he led the first modern study of the drug and found that it helped smokers more than treble their chances of quitting compared to a placebo pill. “I think this is the biggest news in smoking cessation treatment ever,” he says. “Here is a pill that can be produced for next to nothing, that can be bought by even the poorest smoker in India, and that can save literally millions of lives.”

Cytisine is sold as Tabex by Sopharma, a company based in Bulgaria, and as Desmoxan by Aflofarm Pharma of Poland. Sopharma has awarded global rights to market Tabex to a UK-based company called Extab, which claims to be seeking regulatory approval for Tabex in the US, the European Union and Japan.

Journal reference: New England Journal of Medicine, DOI: 10.1056/NEJMoa1407764