Trial findings were published in The Journal of the American Medical Association (JAMA).

Cytisine acts similarly to varenicline and reduces urges to smoke and other nicotine withdrawal symptoms, but at standard dosing (25 days) it was unknown whether it was as effective as varenicline (non-inferior) at promoting smoking cessation.

Researchers at The National Drug and Alcohol Research Centre (NDARC), UNSW Sydney have answered this question by recruiting 1452 Australian adults who smoked daily and were willing to make a quit attempt into a world-leading non-inferiority trial.

The study found the 6-month verified continuous abstinence rates were 11.7 per cent vs 13.3 per cent for the cytisine and varenicline groups respectively.

Whilst non-inferiority was not established, several significant breakthroughs were found. Lead author Dr Ryan Courtney said, “People who smoke often stop use of smoking cessation aids because of side effects such as nausea.”

“Cytisine was found to be more tolerable compared to varenicline, with nausea and abnormal dreams reported less often. An encouraging result that may lead to more smokers taking up this treatment option.”

Promising results towards the end of cytisine treatment period were found with 42.5 per cent of cytisine participants quitting at ~4 weeks compared to 32.3 per cent in the varenicline group.

 “A short treatment period of 25 days for cytisine compared to varenicline (3 months) is an added benefit, but to establish this initial treatment effect so early is very promising. Results from extended dosing studies may even show greater promise for cytisine’s clinical effectiveness,” said Dr Courtney.

The trial found cytisine is a safe and effective aid for helping people quit smoking with enhanced tolerability compared to the best smoking cessation aid.

“Wider access for cytisine worldwide remains an issue,” said Dr Courtney.

“Most people who smoke are found in low- and middle-income countries. Cytisine is a potential way to make tobacco treatment accessible, affordable and effective for governments and people who smoke universally.”

The trial highlights that making cytisine available to more people worldwide could help decrease tobacco’s overwhelming impact on the global burden of disease.

Director of NDARC, Professor Michael Farrell said, “Cytisine presents as a cheap treatment option for so many countries and can assist to reduce tobacco-related harms”.