Smoking Cessation  |  Varenicline [Champix ®]




Smoking Cessation

Varenicline [Champix ®]

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.


Background:

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. 

Prescribing varenicline:

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 works by reducing craving for cigarettes making quitting smoking a little easier and increases the chances of stopping for good. However it’s no magic cure and effort is still required.
  • You need to start varenicline 1-2 weeks prior to your Quit Date. You can smoke as normal prior to your Quit Date and then you should aim not to have a single puff from then on.
  • Nausea, insomnia and vivid dreams are common side effects, but are usually mild to moderate. Taking the tablet with food will reduce the nausea.
  • Some people experience changes in their mood when using Champix and stopping smoking; it is important to let me (your health professional) know if this happens to you.

Contraindications and cautions:

  • Varenicline should not be used in people who have experienced a hypersensitivity reaction to it and it is currently not recommended for use in women who are pregnant or breastfeeding or in adolescents. Varenicline is excreted in urine, almost completed unchanged. While no dosing adjustment is necessary for patients with mild to moderate renal impairment, a reduced dosing frequency of 1 mg once daily is recommended for patients with severe renal impairment.
  • There are no known clinically meaningful drug interactions.
  • Varenicline should be used with caution in people with mental health illness. 3 People with mental health illness may experience worsening of their pre-existing psychiatric illness while taking varenicline and should be monitored closely.
  • Risks and benefits: It is important to discuss the possibility of serious neuropsychiatric symptoms in the context of the benefits of quitting smoking with patients.

Adverse effects:

  • The most commonly reported adverse event is nausea, which is experienced by up to a third of people.
  • Other common adverse effects include headache, insomnia, andabnormal dreams.
  • More serious adverse events, such as depression, suicidal ideation, and suicide have also been reported. Although there is no evidence to demonstrate causality, caution is warranted. The datasheet advises "Patients and their families should be advised that the patients should stop taking CHAMPIX and contact a health care professional immediately if changes in behaviour, agitation or depressed mood, that are not typical for the patients are observed, or if the patient develops suicidal ideation or suicidal behaviour".1


Additional Information:

Frequently asked questions:

  • How does the efficacy of varenicline compare to other medications for smoking cessation?

Varenicline has been shown more effective than bupropion and single product NRT. There are no data comparing varenicline with nortriptyline.

  • Can varenicline be used in people taking anti-depressants?


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.

  • Can varenicline be combined with other smoking cessation medicines?


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.

  • Can varenicline be used in people with cardiovascular disease?

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.

 

References:

  1. Medsafe. New Zealand Medicines and Medical Devices Safety Authority. Varenicline Data Sheet. Available here.
  2. Cahill K, et al. Nicotine receptor partial agonists for smoking cessation. Cochrane Database of Systematic Reviews. 2012.
  3. Purvis TL, et al. Varenicline use in patients with mental illness: an update of the evidence. Expert Opin Drug Saf. 2010;9(3):471-82.
  4. Singh S et al. Risk of serious adverse cardiovascular events associated with varenicline: a systematic review and meta-analysis. Can. Med. Assoc. J. 2011;183(12):1359-66
  5. Prochaska JJ et al. Risk of cardiovascular serious adverse events associated with varenicline use for tobacco cessation: systematic review and meta-analysis. BMJ 2012;344:e2856
  6. European Medicines Agency. (21.07.2011). Press release: European Medicines Agency confirms positive benefit-risk balance for Champix.


Last updated : Friday, July 29, 2016
Next review date : Saturday, July 29,2017


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