Tidings of modest joy

A good story in the Herald about a potentially-important randomised trial conducted in New Zealand.

There’s an anti-smoking pill that was first produced in Bulgaria in 1964, using cytisine, a toxin found in several trees and bushes of the pea family (including common broom and kōwhai).  Cytisine is a partial agonist for the same receptors in the brain that nicotine targets. At the right dose, it keeps nicotine away from the receptors and turns them on, but not all the way. The net effect is that it reduces nicotine craving but isn’t actually enjoyable. The New Zealand trial found offering cytisine was superior to offering nicotine patches or gum for people recruited through Quitline.

Cytisine is similar in mechanism to the much-newer drug varenicline (Champix in NZ, Chantrix in USA). In fact cytisine was the starting point for the development of varenicline, and while the newer drug is superior in some lab tests involving rats, I don’t think they have ever been directly compared in humans.

The disadvantage of cytisine is that it’s less thoroughly studied than varenicline, so less is known about its rare side effects (yes, it was used in communist Europe, but personally I wouldn’t give much for their population mental health data).  The quoted advantage in the Herald story is that it’s much cheaper than alternatives: about a dollar a day. That’s not entirely compelling, since Pharmac pays only $2.40/day, but the price advantage might be more relevant in Brazil or India for the four years left on the varenicline patent.

The other advantage given by the researchers (though not in the Herald story) is more interesting. Because cytisine is a natural product, and because it is present in kōwhai (although that isn’t and wouldn’t be the commercial source), they thought it might be more acceptable to Māori as something that would fit into traditional healing practices (rongoā). The idea was supported by a study involving semi-structured interviews with people identifying as Māori.

Clearly, kōwhai wasn’t traditionally used to treat tobacco addiction, since tobacco addiction wasn’t traditionally a problem. No-one’s suggesting that cytisine should be advertised as actually traditional, and the scenario in the interview was that the drug would only be used if there was proper scientific evidence of safety and effectiveness. This isn’t ‘traditional use’ as a substitute for evidence; it’s traditional use as affiliation.