Varenicline aka Champix

What is Champix?
Champix, generic name varenicline, is a prescription pill designed to help smokers stop smoking.
How does it work?
Champix works primarily in two ways. Firstly, it reduces the smoker's craving for nicotine by binding to nicotine receptors in the brain and reduces the symptoms of withdrawal. Secondly, it reduces the satisfaction a smoker receives when smoking a cigarette.

How successful was it in clinical trials?
In 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.
Has Champix been approved by the European Commission and the FDA for use as an aid to quitting smoking?
The European Commission approved Champix on September 29th, 2006 as a "stop smoking" aid for adults, based on the results from clinical trials. It should be noted that continued abstinence from cigarettes is higher (70% compared with 50%) when patients take the drug for 24 weeks as opposed to 12, so it may be appropriate for patients who have succeeded in quitting smoking at the 12 week point to take the drug for a further 12 weeks.
The FDA approved the drug in May 2006. See FDA approves novel drug for smoking cessation for further details.
Is Champix available on the NHS?
On May 31st, 2007 Nice (the National Institute for Health and Clinical Excellence) published draft guidance recommending that this drug should be available on NHS prescription. Further details on the Final Appraisal Determination period can be found on the NICE website.
It was approved for prescription on the NHS in Scotland on 14th January, 2007.
How is the drug taken and what is the recommended dose?
It is taken orally. For the first three days, the dosage is 0.5 mg once daily (the 0.5 mg tablet is white). For days four to seven, the dosage is 0.5 mg twice a day. From day eight until the end of the treatment, the dose is 1 mg twice a day (the 0.5 mg tablet is blue).