This summary provides a quick reference guide to using varenicline for smoking cessation. It provides information on efficacy, what to say to people who want to use it, prescribing and adverse effects. For full prescribing information healthcare professionals should refer to the New Zealand Formulary.
Varenicline (Champix®) is a partial agonist of the α4β2 nicotinic acetylcholine receptor (nAChR). It works primarily to alleviate urges to smoke and other symptoms of tobacco withdrawal, but also helps to reduce the ‘reward’ associated with smoking.1 Varenicline is fully funded in New Zealand as a smoking cessation treatment, subject to Special Authority criteria, for patients who have previously had two trials of NRT or a trial of bupropion or nortriptyline.
Evidence of efficacy:
A Cochrane systematic review shows that use of varenicline for 12 weeks significantly increases long-term quit rates compared with placebo (28% vs. 12%, Risk Ratio =2.27, 95% CI: 2.02-2.55). 2 There is also added benefit of using an additional 12 weeks of varenicline, compared to placebo, in enhancing 1-year quit rates, although extended use is not currently subsidised.
Varenicline should be started at least 1 week prior to the target quit date. Treatment is started with 0.5 mg daily for the first three days increasing to 0.5 mg twice daily for the next four days and then continued at a dose of 1 mg twice daily for a total of 12 weeks. People should be followed up regularly to check on progress and adverse events.
Things to tell your patients:
Varenicline has been shown more effective than bupropion and single product NRT. There are no data comparing varenicline with nortriptyline.
Yes varenicline can be used in people taking anti-depressants. There are no clinical relevant drug interactions with varenicline. However smokers with a history of depression should be followed up regularly and advised to report any change in their mood to their GP. There have been reports of depression and suicidal ideation in people using varenicline. Although there is no firm evidence of causality, caution is warranted.
No. There is no evidence to suggest that combining varenicline with other smoking cessation medicines increases long-term abstinence rates. Furthermore one of the conditions of varenicline on special authority is that it is not to be used with other smoking cessation medicines.
Yes, varenicline can be used in people with cardiovascular disease. The data on whether varenicline use is associated with an increase risk of cardiovascular adverse events are mixed.4,5
In a 2011 press release the European Medicines Agency’s Committee for Medicinal Products for Human Use (CHMP) and Pharmacovigilance Working Party concluded that the slightly increased risk of cardiovascular events reported by one study (Singh et al 2011) does not outweigh the benefits of Champix in helping people to stop smoking.6The Committee summarized the findings of this meta-analysis saying that events were rare in both groups, but that there was a slightly increased number in the people taking Champix: 1.06% of those taking Champix had an event (52 out of 4,908) compared with 0.82% of those taking placebo (27 out of 3,308). This did not result in a difference in death rates between the two groups. The Committee identified a number of limitations of the meta-analysis, including the low number of events seen, the types of events counted, the higher drop-out rates in people receiving placebo, the lack of information on the timing of events, and the exclusion of studies in which no-one had an event. Because of these limitations, the Committee could not draw robust conclusions from the meta-analysis.
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