University to begin trials of natural quit-smoking drug

Cytisine is extracted from the golden rain plant, a European tree linked to the kowhai. Photo / Mark Mitchell

Auckland researchers are about to recruit smokers into a trial of a quit-smoking tablet from Eastern Europe that has links to the kowhai tree, a New Zealand native.

Tabex, derived from the golden rain tree, has been used for several decades in Bulgaria. There is now hope that if proven effective in New Zealand, it may appeal particularly to Maori, whose smoking rate, at over 40 per cent, is more than double that of the whole population.

Tabex is available from international websites but is not permitted to be sold in New Zealand as it is a medicine and is not yet registered by the Health Ministry.

Auckland University's Clinical Trials Research Unit is about to start recruiting participants, through the national Quitline, for a trial comparing Tabex to nicotine replacement therapy (NRT).

The active ingredient in Tabex is the chemical cytisine, extracted from golden rain.

The research unit says on its website: "As a natural product found in kowhai, cytisine may be a more acceptable smoking cessation treatment for many Maori than current therapies. Cytisine appears to be safe but its effectiveness needs to be further investigated."

The trial's principal investigator, Dr Natalie Walker, emphasised that despite the link to the kowhai tree, people must not experiment by consuming any part of the kowhai, because it is poisonous.

The New Zealand Institute of Horticulture says all parts of the kowhai are poisonous, but mainly the seeds.

Dr Walker said it was uncertain whether the cytisine molecules in kowhai and golden rain were identical. The university's Pharmacy School was exploring this question.

The research unit says the quit-smoking medicines currently available in New Zealand, including NRT, "are not used by many smokers because of side effects and cost".

Tabex is offered by one website for US$19.78 ($27.38), which equates to around $2.14 a day. NRT gum can cost around $3.70 a day, although an eight-week course is available state-subsidised for a co-payment of just $3 in total.

Using NRT doubles a smoker's chance of quitting - boosting it from 5-7 per cent to 10-15 per cent. Tabex has been found to be similarly effective, although the trials this is based on are said to have weaknesses and the results of a large, well-designed Polish trial are awaited.

An Auckland University study based on interviews with Maori smokers and published this month in the journal Nicotine & Tobacco Research suggests that because cytisine occurs in kowhai, it may be a more attractive quit-smoking aid to Maori than products now available.

Dr Marewa Glover and colleagues say in their paper that if cytisine meets New Zealand safety and efficacy requirements, "... cytisine could be very appealing to Maori as a novel smoking cessation product and could boost quitting activity among Maori".

THE PRODUCT

* Name: Tabex

* Purpose: Quit-smoking tablets

* Origin: Made in Bulgaria

* Active ingredient: Cytisine

* Source: Golden rain tree