Abstract
Varenicline is a recently developed medication for smoking cessation, which has been available on prescription since 2006. It is a selective nicotinic acetylcholine receptor partial agonist, and is designed to reduce withdrawal symptoms and to lessen the rewards of continued smoking. Our objective in this article is to assess the efficacy of varenicline as an aid to smoking cessation and to weigh the potential benefits against the possible risks. We identified ten randomized controlled trials and one cohort study with historical controls. In total there were 7999 participants, 5112 of whom received varenicline. Eight of the trials compared varenicline with placebo for cessation, two compared it with nicotine replacement therapy and one tested extended use for relapse prevention. Three of the varenicline/placebo trials also included a bupropion arm. The recommended dosage of varenicline 1 mg twice daily more than doubled the chances of quitting at 6 months or longer, with a relative risk (RR) compared with placebo of 2.38 (95% CI 2.00, 2.84). It also outperformed bupropion (RR 1.52 [95% CI 1.22, 1.88]) and nicotine replacement (RR 1.31 [95%CI 1.01,1.71]). A reduced dosage regimen of 1 mg daily also increased cessation (RR 1.88 [95% CI 1.35, 2.60]). In the trials, varenicline significantly reduced craving and other withdrawal symptoms. The most frequent adverse event was nausea, occurring in 30–40% of varenicline users. However, this was generally reported at mild to moderate levels, diminished over time and was associated with attributable discontinuation rates of between 0.6% and 7.6%. Other commonly occurring adverse events included insomnia, abnormal dreams and headache. Serious adverse events were rare, with no treatment-related deaths during the treatment or follow-up phases.
Postmarketing surveillance has raised new questions about the safety of varenicline. In February 2008, the US FDA issued a public health advisory note, reporting a possible association between varenicline and an increased risk of behaviour change, agitation, depressed mood, and suicidal ideation and behaviour. They have required the manufacturers to revise the labelling of varenicline and the Summary of Product Characteristics, and to issue a medication guide. It is arguable that much of the reported behavioural and mood changes may be associated with nicotine withdrawal, although some effects occurred in people who continued to smoke while taking the medication. In view of the potential, if unproven, risk that varenicline may be associated with serious neuropsychiatric adverse outcomes, patients attempting to quit smoking with varenicline, and their families and caregivers, should be alerted about the need to monitor for neuropsychiatric symptoms, including changes in behaviour, agitation, depressed mood, suicidal ideation and sui-cidal behaviour, and to report such symptoms immediately to the patient’s healthcare provider.
Similar content being viewed by others
References
Department of Health. Smoking kills; a white paper on tobacco, 1998 [online]. Available from URL: http://www.archive.official-documents.co.uk/document/cm41/4177/4177.htm [Accessed 2006 Jan 25]
Fiore MC, Croyle RT, Curry SJ, et al. Preventing 3 million deaths and helping 5 million smokers quit: a national action plan for tobacco cessation. Am J Pub Health 2004; 94(2): 205–10
Danaei G, Vander Hoorn S, Lopez AD, et al. Causes of cancer in the world: comparative risk assessment of nine behavioural and environmental risk factors. Comparative Risk Assessment Collaborating Group (Cancers). Lancet 2005 Nov 19; 366(9499): 1784–93
Mackay J, Eriksen M, Shafey O. The tobacco atlas. 2nd ed. American Cancer Society. Geneva: WHO, 2006
Centers for Disease Control and Prevention. Cigarette smoking among adults: United States, 2006. MMWR 2007 Nov 9; 56(44): 1157–61
Office for National Statistics, Jan 2007. Smoking and drinking among adults, 2006: general household survey 2006 [online]. Available from URL: http://www.statistics.gov.uk/ghs [Accessed 2008 Jun 18]
Hughes JR. Motivating and helping smokers to stop smoking. J Gen Intern Med 2003; 18: 1053–7
West R. Background smoking cessation rates in England 2006 [online]. Available from URL: http://aspsilverbackwebsites.co.uk/smokinginengland/ref/paper2.pdf [Accessed 2008 Jun 20]
USSG US Department of Health and Human Services. The health consequences of smoking: a report of the Surgeon General. Atlanta (GA): USDHHS, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health promotion, Office on Smoking and Health, 2004
Centers for Disease Control and Prevention. Preventing tobacco use among young people: a report of the Surgeon General (executive summary). MMWR Recomm Rep 1994; 43: 1–10
American Psychiatric Association. Diagnostic and statistical manual of mental disorders. 4th ed. Washington, DC: American Psychiatric Association, 1994
Nutt D, King LA, Saulsbury W, et al. Development of a rational scale to assess the harm of drugs of potential misuse. Lancet 2007; 369(9566): 1047–53
Giovino GA, Henningfield JE, Tomar SL, et al. Epidemiology of tobacco use and dependence. Epidem Rev 1995; 17: 48–65
Coe JW, Brooks PR, Vetelino MG, et al. Varenicline: an alpha4beta2nAChR nicotinic receptor partial agonist for smoking cessation. J Med Chem 2005; 48: 3474–7
Papke RL, Heinemann SF. Partial agonist properties of cytisine on neuronal nicotinic receptors containing the beta2 subunit. Mol Pharm 1994; 45: 142–9
Slater YE, Houlihan LM, Maskell PD, et al. Halogenated cytisine derivatives as agonists at human neuronal nicotinic acetylcholine receptor subtypes. Neuropharmacology 2003; 44: 503–15
Foulds J, Burke M, Steinberg M, et al. Advances in pharmacotherapy for tobacco dependence. Expert Opin Emerg Drugs 2004; 9(1): 39–53
Zatonski W, West R, Cedzynska M, et al. The effect of Tabex (cytosine) on successful attempts to stop smoking. Short title: Tabex Smoking Cessation Trial (TASC) [online]. Available from URL: http://www.controlled-trials.com/mrct/trial/256813/tabex2007 [Accessed 2008 Feb 6]
Etter J-F. Cytisine for smoking cessation: a literature review and a meta-analysis. Arch Int Med 2006; 166: 1–7
Action on Smoking and Health 2006. ASH guidance notes: varenicline [online]. Available from URL: http://www.ash.org.uk/files/documents/ASH_447.pdf [Accessed 2007 Jun 12]
National Institute for Health and Clinical Excellence (NICE). Varenicline for smoking cessation [online]. Available from URL: http://www.nice.org.uk/nicemedia/pdf/TA123Guidance.pdf2007 [Accessed 2008 Apr 14]
Summary of product characteristics: varenicline [online]. Available from URL: http://emc.medicines.org.uk/emc/assets/c/html/DisplayDoc.asp?DocumentID=19045 [Accessed 2008 Jul 8]
Benowitz NL. Neurobiology of nicotine addiction: implications for smoking cessation treatment. Am J Med 2008; 121(4A): S3–10
Sands SB, Brooks PR, Chambers LK, et al. A new therapy for smoking cessation: varenicline, a selective nicotinic receptor partial agonist [SYM10C]. Society for Research on Nicotine and Tobacco 11th Annual Meeting; 2005 Mar 20–23; Prague, 14
Cahill K, Stead LF, Lancaster T. Nicotine receptor partial agonists for smoking cessation. Cochrane Database Syst Rev 2008 Jul 16; (3): CD006103
West R, Hajek P, Stead L, et al. Outcome criteria in smoking cessation trials: proposal for a common standard. Addiction 2005; 100: 299–303
Fiore M, Jaen CR, Baker TB, et al. Clinical practice guideline. Treating tobacco use and dependence: 2008 update. USDHHS [online]. Available from URL: http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=hstat2.chapter.28163 [Accessed 2008 Jun 26]
Aubin H-J, Bobak A, Britton JR, et al. Varenicline versus transdermal nicotine patch for smoking cessation: results from a randomised, open-label trial. Thorax 2008; 1: 1–8
Gonzales D, Rennard SI, Nides M, et al. Varenicline, an a4β2 nicotinic acetylcholine receptor partial agonist, vs sustained-release bupropion and placebo for smoking cessation. JAMA 2006; 296(1): 47–55
Jorenby DE, Hays JT, Rigotti NA, et al. Efficacy of varenicline, an a4X2 nicotinic acetylcholine receptor partial agonist, vs placebo or sustained-release bupropion for smoking cessation. JAMA 2006; 296(1): 56–63
Nakamura M, Oshima A, Fujimoto Y, et al. Efficacy and tolerability of varenicline, an a4b2 nicotinic acetylcholine receptor partial agonist, in a 12-week, randomized, placebo-controlled, dose-response study with 40-week follow-up for smoking cessation in Japanese smokers. Clin Ther 2007; 29(6): 1040–56
Niaura R, Hays JT, Jorenby DE, et al. The efficacy and safety of varenicline for smoking cessation using a flexible dosing strategy in adult smokers: a randomized controlled trial. Curr Med Res Opin 2008; 24(7): 1931–41
Nides M, Oncken C, Gonzalez D, et al. Smoking cessation with varenicline, a selective a4b2 nicotinic receptor partial agonist. Arch Intern Med 2006; 166: 1561–8
Oncken C, Gonzalez D, Nides M, et al. Efficacy and safety of the novel selective nicotinic acetylcholine receptor partial agonist varenicline, for smoking cessation. Arch Intern Med 2006; 166: 1571–7
Stapleton JA, Watson L, Spirling LI, et al. Varenicline in the routine treatment of tobacco dependence: a pre-post comparison with nicotine replacement therapy and an evaluation in those with mental illness. Addiction 2008; 103(1): 146–54
Tonstad S, Tonnesen P, Hajek P, et al. Effect of maintenance therapy with varenicline on smoking cessation: a randomized controlled trial. JAMA 2006; 296(1): 64–71
Tsai S-T, Cho H-J, Cheng H-S, et al. A randomized, placebo-controlled trial of varenicline, a selective a4b2 nicotinic acetylcholine receptor partial agonist, as a new therapy for smoking cessation in Asian smokers. Clin Ther 2007; 29(6): 1027–39
Williams KE, Reeves KR, Billing CB, et al. A double-blind study evaluating the long-term safety of varenicline for smoking cessation. Curr Med Res Opin 2007; 23(4): 793–801
Hughes JR, Keely JP, Niaura RS, et al. Measures of abstinence in clinical trials: issues and recommendations. Nic Tob Res 2003; 5(1): 13–25
Hughes JR, Stead LF, Lancastet T. Antidepressants for smoking cessation [Cochrane Review]. In: The Cochrane Library, issue 1,2007 [online]. Available from URL: http://www.mrw.interscience.wiley.com/cochrane/clsysrev/articles/CD000031/frame.html [Accessed 2008 Jul 8]
Stead LF, Perera R, Bullen C, et al. Nicotine replacement therapy for smoking cessation [Cochrane Review]. In: The Cochrane Library, issue 1, 2008 [online]. Available from URL: http://www.mrw.interscience.wiley.com/cochrane/clsysrev/articles/CD000146/frame.html [Accessed 2008 Jul 8]
US Register of Clinical Trials [online]. Available from URL: http://clinicaltrials.gov/ct2/results?term=varenicline [Accessed 2008 Sep 8]
Food and Drug Administration. FDA issues public health advisory on Chantix, 2008 [online]. Available from URL: http://www.fda.gov/CDER/Drug/early_comm/varenicline.htm [Accessed 2008 Apr 14]
Food and Drug Administration. Varenicline (marketed as Chantix) information [online]. Available from URL: http://www.fda.gov/CDER/Drug/infopage/varenicline/default.htm [Accessed 2008 Jul 8]
Food and Drug Administration. Chantix medication guide [online]. Available from URL: http://www.fda.gov/CDER/Offices/ODS/MG/ChantixMG.pdf [Accessed 2008 Jul 8]
Moore TJ, Cohen MR, Furberg CD. Strong safety signal seen for new varenicline risks [online]. Available from URL: http://www.ismp.org/docs/vareniclineStudy.asp [Accessed 2009 Jan 29]
Hauben M, Wilson GG, Reich L. A preliminary quantitative analysis of the spontaneous reporting of selected adverse events with Chantix in the US FDA Adverse Event Reporting System Database [poster]. 10th Annual Meeting of the Society for Research on Nicotine and Tobacco; 2008 Sep 23–26; Rome
National Prescribing Service Ltd. Side effects warning about varenicline (Champix) [online]. Available from URL: http://www.nps.org.au/news_and_media_home/media_releases/repository/side_effects_warning_about_varenicline_champix [Accessed 2009 Jan 29]
Kessler RC, Berglund PA, Borges G, et al. Smoking and suicidal behaviors in the National Comorbidity Survey-Replication. J Nerv Ment Dis 2007 May; 195(5): 369–77
Foulds J. Smoking and suicide [online]. Available from URL: http://www.healthline.com/blogs/smoking_cessation/2008/04/smoking-and-suicide.html [Accessed 2008 Jun 30]
Medicines and Healthcare products Regulatory Agency (MHRA). Drug analysis print_varenicline [online]. Available from URL: http://www.mhra.gov.uk/home/groups/public/documents/sentineldocuments/dap_1214557774601.pdf [Accessed 2008 Jul 7]
NHS prescription cost analysis England 200 [online]. Available from URL: http://www.ic.nhs.uk/webfiles/publications/PCA%20publication/PCA%202007%20complete.pdf [Accessed 2008 Jul 8]
Medicines and Healthcare products Regulatory Agency (MHRA). Detailed drug analysis print interpretation guide [online]. Available from URL: http://www.mhra.gov.uk/Safetyinformation/Howwemonitorthesafetyofproducts/Medicines/TheYellowCardScheme/YellowCarddata/DetailedDrugAnalysis [Accessed 2008 Jul 7]
Acknowledgements
No sources of funding were used to assist in the preparation of this review. The authors have no conflicts of interest that are directly relevant to the content of this review.
Publication note: This paper is based on the Cochrane review ‘Nicotine receptor partial agonists for smoking cessation’.[25]
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Cahill, K., Stead, L. & Lancaster, T. A Preliminary Benefit-Risk Assessment of Varenicline in Smoking Cessation. Drug-Safety 32, 119–135 (2009). https://doi.org/10.2165/00002018-200932020-00005
Published:
Issue Date:
DOI: https://doi.org/10.2165/00002018-200932020-00005