Dr Chris Steele discusses Champix, a new drug available on prescription only that might help you quit smoking. Champix is based on the active ingredient varenicline, and can be twice as effective as other anti-smoking pills. Varenicline is a type of medicine called a nicotinic acetylcholine receptor partial agonist. In clinical trials, 44% of the group treated with Champix had stopped smoking after being treated for 12 weeks, as opposed to 11% of smokers taking the placebo. Over the same duration, it was also shown to be twice as effective as Zyban (bupropion), the other main anti-smoking drug treatment. Champix therefore may be an effective anti-smoking treatment if you are having trouble quitting. The treatment is available via prescription, so you should talk to your GP about this. Champix is known as Chantix in the US and is made by Pfizer.